Interactive science sims
597 virtual practicals and lab sims for chemistry, physics and biology. Every one runs in the browser. Anyone can unlock 2 free, and a free account unlocks up to 5.
Physics
- Hooke's law simLoad 50 g masses onto a spring and watch it stretch the same 12.3 mm every time.
- Converging lens simSlide the lamp along an optical bench; the screen finds the focused image from 1/f = 1/u + 1/v (real-is-positive).
- Vibrating string loop simDrag through 8 modes of a closed loop: whole waves fit round it, and f = n v / C climbs 105 Hz at a time.
- Specific heat capacity of a solid (or water) simHeat a 1.00 kg block or water with a 12 V immersion heater, read the thermometer each minute, fit a line to your graph and work out c, bare or lagged, by joulemeter or by V, I and a stopwatch.
- Cylinder rolling down a ramp: v² against x simMeasure sin θ with a half-metre rule and set square, time a rolling cylinder (or a trolley) over eight distances, fill the table, plot v² against x and find G ÷ (2 sin θ).
- Adding vectors by scale drawing simSet two forces or two velocities, pick a scale, draw them head to tail or as a parallelogram, then measure the resultant with a ruler and a protractor and compare it with the calculated value.
- Atom and nuclide builder simDrag protons, neutrons and electrons into an atom; read Z, A, the element, the nuclide notation and the charge, see whether the nucleus is stable or radioactive, and compare isotopes side by side.
- Centre of gravity of a plane lamina simHang a card from a pin at three holes, mark the plumb line each time, find the centre of gravity where the lines cross, and check it by balancing on a pencil point.
- Charging by rubbing: only electrons move simRub a polythene, acetate or glass rod with wool or silk, watch electrons move from one to the other, then bring the rod near a hanging charged rod or scraps of paper: like charges repel, unlike attract, and a charged rod pulls a neutral one.
- Circular motion: the whirling bung simWhirl a rubber bung on a string: set its speed, radius and mass and read the pull on a newton-meter, let go and watch it leave along the tangent, then hang slotted masses on the string, whirl until the paper clip holds steady, time ten turns and plot F against v².
- Convection in water and air simDrag a Bunsen burner or an immersion heater and a potassium permanganate crystal around a beaker of water and watch the purple trace the convection loop (or stay put when the water is heated at the top), then pull smoke through a candle-heated chimney box and drag the sun to turn a sea breeze into a land breeze.
- Cooling curve of a pure substance simMelt stearic acid (or paraffin wax) in a hot water bath, drag the boiling tube into an air jacket, click the stopwatch on 30 s at a time and read the thermometer at eye level; your readings make a cooling curve with a flat part at the freezing point, which you read off and explain (the wax, a mixture, has none).
- Density: a regular block, an irregular stone and a liquid simMeasure a block with a rule, find a stone's volume by displacement, weigh a liquid in a cylinder, and work out ρ = m ÷ V for each.
- Digital calipers: outside, inside and depth simClose the jaws on a rod, open them in a pipe, push the depth rod into a hole, find and correct the zero error, and choose between a rule, calipers and a micrometer.
- Digital micrometer screw gauge: zero it, then measure a wire simFind and correct a positive or negative zero error, close the jaws on a wire with the ratchet, measure the diameter at three places, average, and work out A = πd²/4.
- EM spectrum explorer: radio waves to gamma rays simDrag a slider along the spectrum on a log scale: λ and f change in opposite directions while c stays 3.0 × 10⁸ m/s, and each band shows its source, detector, uses and dangers.
- Free-body diagram builder simDrag weight, normal contact, tension, friction, air resistance, driving force and push onto a book, a lamp, a box, a parachutist, a lift, a car and two joined blocks; set each size, check the diagram, and see the resultant and the motion it predicts.
- Friction: pulling a block with a newton-meter simPull a block with a newton-meter: friction matches the pull until the block slips, then drops to a smaller sliding friction. Change the surface, oil it, add masses, and plot friction against the normal force.
- Image in a plane mirror simFind the image of a pin in a plane mirror by moving a search pin until there is no parallax, or with two sight lines, then measure u and v with a rule and plot v against u.
- Impulse and safety: crumple zones, cushions, seat belts and airbags simCrash a trolley into a force sensor through a crumple zone or foam pad you drag thicker or thinner, drop an egg onto a tile, a towel or foam, and crash-test a car with and without a seat belt and airbag; place the logger's cursors, work out Δp and F = Δp ÷ Δt, and see the same area under a lower, wider force–time graph.
- Law of reflection with a ray box simAim a ray box at a plane mirror, mark the rays with crosses, read i and r from the normal with a protractor, and plot r against i. Then see a rough surface scatter the light.
- Levers, spanners and gears simPull on a spanner with a newton-meter at different distances and angles and see the perpendicular distance, read the force that turns the nut and work out its moment; drag the pivot of a crowbar or the load in a wheelbarrow; turn a gear pair and watch speed traded for turning effect.
- Mass and weight on other worlds simHang a load on a newton-meter and weigh it on a beam balance on Earth, the Moon, Mars, Jupiter and in deep space. The newton-meter reading changes; the beam balance does not. Plot W against m and read g from the gradient.
- Mercury barometer simRead a mercury barometer with a metre rule, tilt the tube, widen it and push it deeper to see the vertical height stay at about 760 mm, change the weather and the altitude, work out p = ρgh, and spot the air bubble that makes h too small.
- Metre rule and tape: zero error, end error and parallax simSlide an object along a worn rule or a tape, put your eye straight above each end, read to 0.1 cm and subtract the start from the end.
- Newton's third law with force sensors simTwo trolleys with force sensors tug, push, collide and spring apart. Zero the sensors, then watch both traces come out equal and opposite at every instant, whatever the masses; then sort pairs from balanced forces.
- Pressure in a liquid: depth and density simLower a pressure probe into water, salt water or cooking oil, correct the meter's zero, turn the probe and change the vessel, then plot p against h and work out ρ from the gradient; a can with holes shows the deepest jet spurting hardest.
- Ray diagram builder: converging lens simMove an object in front of a thin converging lens, draw the three standard rays yourself with a pencil and ruler, find where they meet, read the image distance and height off the grid and name the image, for all five object positions including the magnifying glass.
- Ripple tank: wave speed, reflection, refraction and diffraction simSet the dipper's frequency, freeze the waves with a strobe, measure λ over several waves and find v = f λ; then add a barrier, a shallow plate or a gap.
- Series and parallel rules simWire the same lamps in series or in parallel, drag ammeters and voltmeters into place, unscrew a lamp, and find the rules for current, p.d. and resistance from your own readings.
- Simple pendulum: timing, and finding g simSet the length, time 20 oscillations, fill the table and find g from the gradient of T² against l.
- Sound: vibrations, a medium and the oscilloscope simDrag the microphone and turn the oscilloscope's time-base and Y-gain to see louder = taller and higher pitch = more waves; read n waves over d divisions, work out T and f = 1 ÷ T and have each step checked; watch the air's compressions and rarefactions; pump the air out of a bell jar and graph the fading sound; and race a pulse through steel, water and air.
- Speed of sound by echo simClap in front of a wall, get in time with the echoes and time a run of them with a stopwatch, work out v = 2d ÷ t and see why one echo is too short to time by hand; then time a pulse between two microphones in air, water and steel with v = d ÷ t and compare the three speeds on one graph.
- Stability and toppling simTilt a hinged board with a model bus, a bottle of sand or a wooden cone on it and watch the weight line from G leave the base as it topples; then measure the toppling angle of six wooden blocks on the protractor and plot tan θ against (b ÷ 2) ÷ h.
- States of matter: the particle model simDrag a heater slider to take 50 g of ice to water to steam and back while a magnified box shows its particles go from a vibrating lattice, to sliding past each other, to flying apart and hitting the walls; record the heating curve with its flat parts, then squash sealed syringes of air, water and wax.
- Three forces in equilibrium: the triangle of forces simHang a load from two newton-meters, read the tensions and the angles, then draw the closed triangle of forces to scale and check it against the meters.
- U-tube manometer simJoin a U-tube manometer to the gas tap, a flask squeezed by a syringe or your own breath, read both levels to the nearest mm, find h and work out Δp = ρgh and the gas's pressure, then swap the water for oil or mercury and widen one arm to see what changes.
- Walk the graph: match a motion graph by walking simWalk in front of a motion sensor so your displacement–time, velocity–time, distance–time or speed–time line matches a target, then measure it with the gradient and area tools.
- Work done and power simDrag a newton-meter to pull a box along the bench and lift a load up steps, read the force and the distance moved in its direction to find W = F × d, then weigh a runner, count the stairs and time them walking and running to find their power P = W ÷ t.
- Waves on a string simTune a vibration generator until standing waves appear, measure the nodes, and find the wave speed from v = f λ and a graph of f against 1/λ.
- Appliance power and the electricity bill simSwitch on a kettle, toaster, fan and LED lamp, set a timer, run them and watch an energy meter count kilowatt-hours, then record each run and work out the cost at a price per kWh you choose.
- Dispersion and colour simShine a ray box through a glass prism to spread white light into a spectrum, slide colour filters into the beam, and light six coloured blocks with red, green or blue light to see which ones turn black.
- Pressure = force ÷ area: a brick on sand simTurn a real brick onto each of its three faces in a tray of sand and add 1 kg masses, record the pressure each time, and plot pressure against 1/area to see the same force give more pressure on a smaller area.
- Size ladder: atom to Earth simDrag a zoom slider along a powers-of-ten rail from 10⁻¹⁰ m to 10⁷ m and record the real objects that come into view, from a hydrogen atom to the Earth, with their sizes in prefixes and standard form.
- Leslie cube: emitters and absorbers of infrared simPour hot water into a Leslie cube, read a thermopile 10 cm from each face over three rounds as it cools, then time which waxed pin drops first beside a radiant heater.
- Refraction through a rectangular glass block simSet a ray box or pins, mark the ray, measure i and r with a protractor, and find n from the gradient of sin i against sin r.
- Black-body radiation: temperature and colour simTurn up the supply to a lamp and watch its filament go from giving out only infrared to dull red, orange, yellow and yellowish white while its emission curve's peak moves to shorter wavelengths and its total power climbs; then warm a black or shiny can in a lamp's light until it absorbs as fast as it gives out, and see the same balance set the Earth's temperature.
- Charge flow and current simClose the switch on a real series loop and watch the lamp light at once while every ammeter reads the same; drag a magnifier over any lead to see the electrons drift from − to + against the conventional current, time a run, work out Q = I × t yourself (✗ reasons for mA and ms) and check it against a coulomb counter.
- Combining resistors simDrag real resistors into the clips of a resistance board to wire them in series or in parallel, measure V and I with real digital meters, work out R = V ÷ I from your own readings and check it against the series and parallel formulas, and see that adding a parallel branch lowers the total while adding in series raises it.
- Efficiency: a motor lifting a load simSet the supply's voltage and the load, then time a small geared motor winding a slotted-mass load up beside a half-metre rule: read the energy in from a joulemeter (or V × I × t), work out the useful energy m g Δh and the efficiency, watch a Sankey diagram of where the energy went draw itself, and plot how the efficiency changes with the load.
- Electric field patterns simSwitch on an EHT supply joined to electrodes in a dish of castor oil and watch semolina grains line up into the field pattern of a point, a charged sphere, two points or two parallel plates; drag the electrodes, show field lines running from + to −, and drop in a small + or − test charge to see the force on it.
- Energy resources: power a town simDrag the faders on a model town's control desk to switch on coal, gas, nuclear, biofuel, geothermal, hydroelectric, wind, solar and tidal power, change the wind, the sky and the hour, and see hour by hour whether the supply meets the town's demand, with scores for hours met, CO₂, renewables and rough cost; save your mixes to a table and sort the resources by renewable, from the Sun and available at any hour.
- Evaporation and boiling simWeigh a dish of water or ethanol on a balance as it evaporates, changing the temperature, the surface area and a desk fan's air speed; watch a wet-bulb thermometer cool below a dry one; then heat water on a hotplate until bubbles form all through it and the temperature stays at the boiling point.
- Floating, sinking and upthrust simLower a cylinder on a newton-meter into water, salt water or cooking oil from a displacement can that spills into a beaker on a balance: watch the reading fall as the upthrust grows, find U = weight in air − reading in the liquid, predict float or sink from the densities, and see a wooden block float deeper in oil and higher in salt water; cards show a hydrometer and a steel boat.
- Magnetic field of bar magnets simPlot the field round a bar magnet the classic way, moving a plotting compass and marking a pencil dot at each end of its needle, then sprinkle iron filings, put two magnets N–N (finding the neutral point X) and N–S, and add the Earth's field to see where it cancels the magnet's.
- Magnetic field of a wire and a solenoid simPass a current up a wire through a card ringed with plotting compasses and iron filings, reverse it and raise it with a rheostat, then thread a coil through the card and see its field look like a bar magnet's, with its N end found by the right-hand grip rule and made stronger by more current, more turns and an iron core.
- Potential divider and potentiometer simDrag the sliding contact of a real slide rheostat used as a potentiometer (or choose R1 and R2 on a two-resistor board), measure V_in and V_out with a digital voltmeter, record V_out against the contact's position in an empty table, see your own points make a straight best-fit line through the origin, and check V_out = V_in × R2 ÷ (R1 + R2) against your readings; a load across the output (beyond the syllabus) bends the line.
- Thermal expansion simHeat a brass ball until it sticks in a ring and heat the ring until it drops through, watch a bimetallic strip bend away from a contact and switch a lamp like a thermostat, then warm water and air side by side in a water bath and see the gas expand far more than the liquid.
- Ultrasound: sonar and scanning simSail a model ship over a sea bed in a water tank, send ultrasound pulses and read the echo times on an oscilloscope to map the depth with d = v t ÷ 2; then slide a probe over a gel block to get echoes from every boundary inside (and none without gel), and over a steel bar to find a hidden crack.
- Using ammeters and voltmeters simDrag the meters' plugs onto a real bench circuit: put the ammeter in series and the voltmeter across the lamp, red to +, see what really happens when they are wired wrongly (a blown fuse, a dark lamp), pick the range, read the needle to half a division looking straight on, correct a zero error, compare a digital display, and work out the lamp's resistance from your own readings.
- Wiring a mains plug simDrag the brown, blue and green-and-yellow cores onto the terminals of a real three-pin plug seen from the back, tighten the screws, choose the strip length, work out I = P ÷ V and fit the right fuse, clamp the cable grip on the sheath, then run the checks, which name every fault, why it matters and what it would do, and see what earthing does when a live wire touches the metal case.
- Momentum: collisions on an air track simLoad two gliders, fire them at each other in elastic, sticky or explosion collisions, time them through light gates, and show that the total momentum is the same before and after.
- Specific latent heat: melting ice and boiling water simMelt ice with an immersion heater beside a control funnel, or boil water on a balance, record the joulemeter and the masses each minute, and find the specific latent heat from your graph.
- Electron beam in a magnetic field simFire an electron beam across a deflection tube's screen between a pair of coils, predict with Fleming's left-hand rule (current opposite to the electrons' flow) which way it bends, turn up the coil current to watch it bend, reverse the field, and predict a positive beam as a thought experiment.
- Decay equations on the N–Z chart simChoose α, β or γ decay (or follow the uranium-238 chain to lead-206), move a magnetic nucleus counter to the new nucleus on an N–Z chart board, and balance the decay equation by typing the new nucleus's A, Z and symbol and the particle's numbers.
- Electromagnet strength simLower a coil wound on a tube onto a dish of paper clips, switch on, lift it and count the clips it holds, then change the number of turns, the current (rheostat and ammeter) or the core (none, iron nail, steel nail) one at a time, fill a fair-test table and plot clips against turns or current with a best line, and see the steel keep some clips when switched off.
- Electromagnets at work: relay, bell, circuit breaker simClose a relay's coil switch and watch a 58 mA coil current pull the armature down and switch on a separate 12 V lamp circuit carrying 2.91 A; step an electric bell through its make-and-break cycle one stage at a time; switch on lamps or join a fault until a model circuit breaker trips, and find that it will not reset until the fault is removed.
- Electrostatics at work and as a hazard simSwitch on a model smoke precipitator and watch the charged smoke stick to the earthed plates, charge a spray gun and see the paint wrap round an earthed can, and pump fuel into a tanker with and without its earthing strap to see why a spark can jump in the fuel vapour.
- E.m.f. and p.d.: energy per charge simDrag 1.5 V cells into a four-bay battery holder, flip one round and see it subtract, move a voltmeter's plugs across one cell or the whole battery, and watch energy-per-coulomb bars show each coulomb gaining E joules in the cells and giving it all up in two lamps; then work out the total e.m.f., the energy given to 2 C and the p.d. across the second lamp yourself.
- Fission chain reaction and fusion simDrag the control rods of a cut-away reactor core model and run the chain reaction one generation per click, watching U-235 nuclei split and graphing your own run, until the chain is steady; then turn the heating dial of a cut-away tokamak model and fire hydrogen-2 and hydrogen-3 nuclei together to see why fusion needs a very high temperature; balance the fission and fusion equations.
- Force on a current-carrying conductor simPredict with Fleming's left-hand rule which way a copper rod on two rails between magnet poles will roll, switch on and watch it, then swap the supply's leads, turn the magnet over or both; hold the rod with a force sensor to plot force against current, work out F = BIL (GCSE Higher tier), and watch an a.c. current move a loudspeaker's cone in and out.
- Induced magnetism: iron and steel simLower a bar magnet onto a soft-iron or a steel bar held in a clamp, dip the bar in a dish of paper clips and count the chain it holds, lift the magnet away and count again, read the bar's induced pole on a plotting compass, then magnetise the bars (stroking, d.c. coil), weaken them (hammering) or demagnetise them (heating, a.c. coil) and test them, in a table of your own counts.
- Power transmission and the National Grid simDrag a plug along a step-up transformer's taps on a model power line and watch the cable current and its I²R loss fall and the town's lamps brighten, work out the loss from your own ammeter readings, then set a real grid's transmission voltage and see the loss fall as 1 ÷ V².
- Using radioactivity: choose the source simFor five jobs (a paper thickness gauge, a medical tracer, a smoke alarm, sterilising, dating) pick a source from a lead-lined box by its radiation and half-life, try it on a real bench by dragging the apparatus and looking again later, then commit; also sort four cases into irradiated or contaminated.
- The a.c. generator and d.c. dynamo simTurn a coil between magnet poles, read the peak e.m.f. and period from an oscilloscope, work out the frequency, then swap in a commutator for d.c. (dynamo mode, AQA only) and load it with a lamp.
- Charging by induction and the gold-leaf electroscope simThe student rubs a rod, charges two spheres (or one, by earthing it) without touching them, and tests the charges with a gold-leaf electroscope.
- Circuit builder simThe student drags real cells, lamps, resistors, meters and sensors onto a board, wires them with plug leads and sees the circuit work, then checks it as a circuit diagram.
- Faults, fuses, earthing and circuit breakers simThe student works out each appliance's current and fuse, then makes earth faults, short circuits and shocks happen in a metal kettle and sees how the earth wire, fuse and circuit breaker keep the user safe.
- Gas pressure in a syringe: volume, temperature and particles simThe student squeezes a sealed syringe of air and heats it in a water bath, reads the pressure gauge, fills the tables and finds Boyle's law and absolute zero from graphs of their own readings.
- Random decay and half-life simCount background, shake a protactinium generator, record 10 s counts with a GM tube, plot the corrected decay curve, read and average the half-life, then watch 400 model nuclei decay at random.
- Resistance of a wire: length and thickness simSlide a crocodile clip along a constantan wire, read the voltmeter and ammeter, work out R = V ÷ I, plot R against length and compare three thicknesses of wire.
- Sensor circuits: the LDR and the thermistor simThe student measures how an LDR's resistance falls with light and a thermistor's with temperature, plots their own graphs, then builds a night light and a fire alarm from a potential divider and finds which way round each sensor must go.
- Thermal insulation and cooling simThe student wraps a beaker of hot water in different materials, reads the thermometer every minute, and compares the cooling curves to find the best insulator.
- The transformer simBuild a step-up or step-down transformer from a demountable kit, read the voltages and currents into a table, and work out the turns ratio, the currents and the efficiency.
- Day, seasons and Moon phases simDrag a classroom tellurion's arm round its lamp, spin its tilted globe and turn its Moon, predict the season and the Moon's phase before they are shown, work out the noon Sun's height in Singapore and London and graph the day length through the year.
- Orbits of planets and satellites simSwing the arm of a classroom orbit demonstrator round the Sun one equal step of time at a time, set the orbit's size and shape, predict where a planet on an ellipse is fastest and see why from energy, watch the pull of gravity always point to the centre, then work out v = 2πr ÷ T for satellites from a low orbit to a geostationary one and graph speed against radius.
- Life of a star, and red shift simSlide galaxy-spectrum slides into a viewer beside a school spectrometer and hydrogen tube, put a cursor on each galaxy's red hydrogen line, work out its shift and graph it against distance; then drag a star-life model set's mass slider and step through the life of a star like the Sun and of a much more massive one.
- Area = displacement simA tacho-generator on the end pulley's shaft makes a voltage in step with the trolley's speed, and the pen's servo sets the pen 800 mm above the zero l
- A ball thrown up simThe launcher fires the ball straight up at 3 m/s.
- Brownian motion simSmoke specks scatter the lamp's light, so they show as bright points; they jiggle about at random, never settling.
- The chart recorder simThe trolley's cord loop turns a 72 mm pulley at the end of the track.
- The coin and the feather simAir pushes back on anything moving through it, and the push (air resistance) grows with speed.
- Conduction along rods simHeat is conducted along each rod from the hot end: the particles there vibrate more and pass energy on to their neighbours, and in metals free electro
- Cylinder down a ramp simLet go from rest, the cylinder speeds up steadily (a = 2/3 g sin 4° = 0.465 m/s² for a rolling solid cylinder, g = 10 m/s²), so d = ½at².
- Distance and displacement simThe trundle wheel is 1 m round, so it clicks once for every metre it rolls: it counts every bend and detour, the distance along the path, 8.64 m from A to B.
- Simple d.c. motor simA coil of 40 turns sits in a field of 0.1 T between the poles.
- Force, mass and acceleration simThe pull on the trolley is the weight of the hanging masses: each 20 g mass weighs 0.2 N.
- Free fall, flash by flash simThe switch cuts the electromagnet's current and the ball falls from rest.
- Galileo's ramp with bells simThe ball starts from rest and speeds up steadily (a = 5/7 g sin 3° = 0.374 m/s² for a rolling ball, g = 10 m/s²), so the distance it has rolled grows
- Heating ice to steam simThe 200 W heater supplies 200 J every second.
- The hydraulic press simPressure = force ÷ area.
- I-V characteristics simSliding the rheostat's contact changes how much resistance wire the current passes through, so it changes the current, and the p.d.
- Average speed: two light gates simWhen the front edge of the card cuts the first gate's beam the timer starts; when it cuts the second gate's beam the timer stops.
- Electromagnetic induction simMoving the magnet changes the magnetic flux through the coil's turns, and a changing flux linkage induces an e.m.f.
- The principle of moments simThe moment of a force is the force × the perpendicular distance from the pivot to its line of action.
- Motion sensor and data logger simThe sensor sends a pulse of ultrasound 20 times a second.
- Energy in a pendulum simPulled aside, the bob is higher than at the bottom, so it has energy in its gravitational potential store: m g h.
- Alpha, beta and gamma simAlpha particles are big and heavily charged: they ionise strongly and are stopped by a sheet of paper, or a few centimetres of air.
- Refraction and total internal reflection simThe beam enters the curved side along a radius, so it meets that surface square on and does not bend.
- Speed and velocity simSpeed is how fast; velocity is how fast in a stated direction.
- Waves on a slinky simA wave carries energy along the slinky without carrying the slinky with it: watch the red coil move to and fro about its own place while the wave passes.
- Stopping distance simStopping distance = thinking distance + braking distance.
- Terminal velocity simThree forces act on the ball: its weight down, and upthrust and drag up.
- Ticker-tape timer simThe timer's arm strikes the tape through a carbon disc 50 times a second, so the gap between dots is the distance moved in 1/50 s.
- A U-turn: distance and displacement simThe odometer on the trolley turns with its wheel whichever way it rolls, so it adds up every move: the distance, a scalar.
- One lap of a 400 m track: distance vs displacement animationAn animation that plays by itself on a loop: one lap of a 400 m track: distance vs displacement.
- Runner versus racing car acceleration animationAn animation that plays by itself on a loop: runner versus racing car acceleration.
- Three ropes in a tug of war animationAn animation that plays by itself on a loop: three ropes in a tug of war.
- Braking force and stopping distance animationAn animation that plays by itself on a loop: braking force and stopping distance.
- Shunting engine and three wagons animationAn animation that plays by itself on a loop: shunting engine and three wagons.
- Three mooring ropes force triangle animationAn animation that plays by itself on a loop: three mooring ropes force triangle.
- Bow force-distance graph animationAn animation that plays by itself on a loop: bow force-distance graph.
- Two flat tracker graphs animationAn animation that plays by itself on a loop: two flat tracker graphs.
- Particle spacing and compression animationAn animation that plays by itself on a loop: particle spacing and compression.
- How a thermometer reads temperature animationAn animation that plays by itself on a loop: how a thermometer reads temperature.
- Water and air heating compared animationAn animation that plays by itself on a loop: water and air heating compared.
- Hydrostatic pressure in centimetres and metres animationAn animation that plays by itself on a loop: hydrostatic pressure in centimetres and metres.
- Gold bar scaled in three dimensions animationAn animation that plays by itself on a loop: gold bar scaled in three dimensions.
- One pipe, two manometers animationAn animation that plays by itself on a loop: one pipe, two manometers.
- Manometer pressure from column weight animationAn animation that plays by itself on a loop: manometer pressure from column weight.
- Absolute pressure reading animationAn animation that plays by itself on a loop: absolute pressure reading.
- Black and shiny panels in infrared animationAn animation that plays by itself on a loop: black and shiny panels in infrared.
- Greenhouse absorbing and re-radiating animationAn animation that plays by itself on a loop: greenhouse absorbing and re-radiating.
- Blanket and black-bulb thermometer animationAn animation that plays by itself on a loop: blanket and black-bulb thermometer.
- Kettle and solar thermal heating animationAn animation that plays by itself on a loop: kettle and solar thermal heating.
- Internal energy in survival flasks animationAn animation that plays by itself on a loop: internal energy in survival flasks.
- Tsunami buoy displacement-time graph animationAn animation that plays by itself on a loop: tsunami buoy displacement-time graph.
- Two wave graphs, one speed animationAn animation that plays by itself on a loop: two wave graphs, one speed.
- Time trace to distance snapshot animationAn animation that plays by itself on a loop: time trace to distance snapshot.
- Four heartbeats and the period animationAn animation that plays by itself on a loop: four heartbeats and the period.
- Surfer bobbing on a travelling wave animationAn animation that plays by itself on a loop: surfer bobbing on a travelling wave.
- Radio wave period animationAn animation that plays by itself on a loop: radio wave period.
- Tsunami carries energy, not water animationAn animation that plays by itself on a loop: tsunami carries energy, not water.
- Earthquake longitudinal and transverse waves animationAn animation that plays by itself on a loop: earthquake longitudinal and transverse waves.
- One spring, two wave types animationAn animation that plays by itself on a loop: one spring, two wave types.
- Amplitude versus crest-to-trough height animationAn animation that plays by itself on a loop: amplitude versus crest-to-trough height.
- Same amplitude on two graph axes animationAn animation that plays by itself on a loop: same amplitude on two graph axes.
- Hummingbird wingbeat period animationAn animation that plays by itself on a loop: hummingbird wingbeat period.
- Zero displacement, opposite directions animationAn animation that plays by itself on a loop: zero displacement, opposite directions.
- Buoy after 7.5 seconds animationAn animation that plays by itself on a loop: buoy after 7.5 seconds.
- Doubling frequency at the same height animationAn animation that plays by itself on a loop: doubling frequency at the same height.
- Wave speed from frequency and wavelength animationAn animation that plays by itself on a loop: wave speed from frequency and wavelength.
- Wavelength from a given point X animationAn animation that plays by itself on a loop: wavelength from a given point X.
- Sonar pulse travel time animationAn animation that plays by itself on a loop: sonar pulse travel time.
- Period from a time graph, wavelength from a snapshot animationAn animation that plays by itself on a loop: period from a time graph, wavelength from a snapshot.
- Ripple tank snapshot: distances and displacements animationAn animation that plays by itself on a loop: ripple tank snapshot: distances and displacements.
- Compression centre: zero displacement, maximum pressure animationAn animation that plays by itself on a loop: compression centre: zero displacement, maximum pressure.
- Sound particles and the time axis animationAn animation that plays by itself on a loop: sound particles and the time axis.
- Loudspeaker sound wavelength animationAn animation that plays by itself on a loop: loudspeaker sound wavelength.
- Echo distances: add or subtract animationAn animation that plays by itself on a loop: echo distances: add or subtract.
- Speaker in a bell jar swings a ball animationAn animation that plays by itself on a loop: speaker in a bell jar swings a ball.
- Bell jar in three stages animationAn animation that plays by itself on a loop: bell jar in three stages.
- Sound pressure in compressions animationAn animation that plays by itself on a loop: sound pressure in compressions.
- No sound across the vacuum of space animationAn animation that plays by itself on a loop: no sound across the vacuum of space.
- Sound speed in steel, water and air animationAn animation that plays by itself on a loop: sound speed in steel, water and air.
- Sonar echo round trip animationAn animation that plays by itself on a loop: sonar echo round trip.
- Echo reflection and the microphone animationAn animation that plays by itself on a loop: echo reflection and the microphone.
- Tuning fork, 500 Hz and 2 ms animationAn animation that plays by itself on a loop: tuning fork, 500 Hz and 2 ms.
- Infrared forehead thermometer animationAn animation that plays by itself on a loop: infrared forehead thermometer.
- Infrared optical fibre data link animationAn animation that plays by itself on a loop: infrared optical fibre data link.
- Infrared and radio carry the same message animationAn animation that plays by itself on a loop: infrared and radio carry the same message.
- Passive RFID tag powered by the reader animationAn animation that plays by itself on a loop: passive RFID tag powered by the reader.
- X-ray: bone looks bright on the detector animationAn animation that plays by itself on a loop: x-ray: bone looks bright on the detector.
- Ultraviolet effects and uses animationAn animation that plays by itself on a loop: ultraviolet effects and uses.
- Blue light curing a dental filling animationAn animation that plays by itself on a loop: blue light curing a dental filling.
- Sunlight crossing a vacuum: electric and magnetic fields animationAn animation that plays by itself on a loop: sunlight crossing a vacuum: electric and magnetic fields.
- Electromagnetic spectrum wavelengths by object size animationAn animation that plays by itself on a loop: electromagnetic spectrum wavelengths by object size.
- Angle of incidence measured from the normal animationAn animation that plays by itself on a loop: angle of incidence measured from the normal.
- Plane mirror ray diagram: real and virtual rays animationAn animation that plays by itself on a loop: plane mirror ray diagram: real and virtual rays.
- Moving a mirror moves the image twice as far animationAn animation that plays by itself on a loop: moving a mirror moves the image twice as far.
- What a plane mirror lets you see animationAn animation that plays by itself on a loop: what a plane mirror lets you see.
- Smooth and rough surfaces: regular and diffuse reflection animationAn animation that plays by itself on a loop: smooth and rough surfaces: regular and diffuse reflection.
- Seeing an object by reflected light animationAn animation that plays by itself on a loop: seeing an object by reflected light.
- The image in a plane mirror animationAn animation that plays by itself on a loop: the image in a plane mirror.
- Refraction makes a fish look higher than it is animationAn animation that plays by itself on a loop: refraction makes a fish look higher than it is.
- Light entering glass straight on changes speed, not direction animationAn animation that plays by itself on a loop: light entering glass straight on changes speed, not direction.
- Converting a surface angle to an angle from the normal animationAn animation that plays by itself on a loop: converting a surface angle to an angle from the normal.
- A glass block shifts a ray sideways animationAn animation that plays by itself on a loop: a glass block shifts a ray sideways.
- The two angles in the refractive index formula animationAn animation that plays by itself on a loop: the two angles in the refractive index formula.
- Critical angle and total internal reflection in a fibre animationAn animation that plays by itself on a loop: critical angle and total internal reflection in a fibre.
- Counting electrons into charge and current animationAn animation that plays by itself on a loop: counting electrons into charge and current.
- Circuit symbols: cell and battery animationAn animation that plays by itself on a loop: circuit symbols: cell and battery.
- Where the ammeter and voltmeter go animationAn animation that plays by itself on a loop: where the ammeter and voltmeter go.
- The resistance experiment: V against I animationAn animation that plays by itself on a loop: the resistance experiment: V against I.
- Conventional current and electron flow animationAn animation that plays by itself on a loop: conventional current and electron flow.
- E.m.f. and potential difference animationAn animation that plays by itself on a loop: e.m.f. and potential difference.
- Work done by a cell: W = QV animationAn animation that plays by itself on a loop: work done by a cell: W = QV.
- Resistance: R = V / I animationAn animation that plays by itself on a loop: resistance: R = V / I.
- Resistors in series and in parallel animationAn animation that plays by itself on a loop: resistors in series and in parallel.
- Resistance of a wire: length and thickness animationAn animation that plays by itself on a loop: resistance of a wire: length and thickness.
- Resistivity of five metals animationAn animation that plays by itself on a loop: resistivity of five metals.
- Resistor colour bands animationAn animation that plays by itself on a loop: resistor colour bands.
- I-V graph of a filament bulb animationAn animation that plays by itself on a loop: i-V graph of a filament bulb.
- What is shared in series and in parallel animationAn animation that plays by itself on a loop: what is shared in series and in parallel.
- One break stops a series circuit animationAn animation that plays by itself on a loop: one break stops a series circuit.
- Voltage shared along a series loop animationAn animation that plays by itself on a loop: voltage shared along a series loop.
- Current splitting at a junction animationAn animation that plays by itself on a loop: current splitting at a junction.
- Finding an unknown resistor in a parallel branch animationAn animation that plays by itself on a loop: finding an unknown resistor in a parallel branch.
- Each parallel branch gets the full supply voltage animationAn animation that plays by itself on a loop: each parallel branch gets the full supply voltage.
- Series and parallel rules compared animationAn animation that plays by itself on a loop: series and parallel rules compared.
- Combining series chains inside parallel branches animationAn animation that plays by itself on a loop: combining series chains inside parallel branches.
- Finding an unknown resistor from the total resistance animationAn animation that plays by itself on a loop: finding an unknown resistor from the total resistance.
- From one branch's p.d. back to the battery voltage animationAn animation that plays by itself on a loop: from one branch's p.d. back to the battery voltage.
- Where the switch goes to darken two lamps animationAn animation that plays by itself on a loop: where the switch goes to darken two lamps.
- The potential divider animationAn animation that plays by itself on a loop: the potential divider.
- Reading a nuclide symbol animationAn animation that plays by itself on a loop: reading a nuclide symbol.
- The atom: nucleus, electrons and isotopes animationAn animation that plays by itself on a loop: the atom: nucleus, electrons and isotopes.
- Alpha, beta and gamma between charged plates animationAn animation that plays by itself on a loop: alpha, beta and gamma between charged plates.
- Random radioactive decay animationAn animation that plays by itself on a loop: random radioactive decay.
- Nuclide equations: alpha and gamma animationAn animation that plays by itself on a loop: nuclide equations: alpha and gamma.
- Balancing a decay equation to find the new element animationAn animation that plays by itself on a loop: balancing a decay equation to find the new element.
- Background radiation and half-life animationAn animation that plays by itself on a loop: background radiation and half-life.
- Nuclear fission and nuclear fusion animationAn animation that plays by itself on a loop: nuclear fission and nuclear fusion.
- Radiation gauge measuring steel thickness animationAn animation that plays by itself on a loop: radiation gauge measuring steel thickness.
- Half-life of sources for food irradiation and smoke alarms animationAn animation that plays by itself on a loop: half-life of sources for food irradiation and smoke alarms.
- Radioactive dating by counting half-lives animationAn animation that plays by itself on a loop: radioactive dating by counting half-lives.
- Nuclide symbols: upper and lower numbers animationAn animation that plays by itself on a loop: nuclide symbols: upper and lower numbers.
- Testing two bars with a magnet animationAn animation that plays by itself on a loop: testing two bars with a magnet.
- Aligned magnetic domains in iron animationAn animation that plays by itself on a loop: aligned magnetic domains in iron.
- A lifting magnet holding a chain of nails animationAn animation that plays by itself on a loop: a lifting magnet holding a chain of nails.
- A coil magnetising a screwdriver animationAn animation that plays by itself on a loop: a coil magnetising a screwdriver.
- Stroking a steel needle with one magnet pole animationAn animation that plays by itself on a loop: stroking a steel needle with one magnet pole.
- What makes a coil a solenoid animationAn animation that plays by itself on a loop: what makes a coil a solenoid.
- Soft iron core in a relay animationAn animation that plays by itself on a loop: soft iron core in a relay.
- Field lines around a bar magnet animationAn animation that plays by itself on a loop: field lines around a bar magnet.
- Field between a magnet and soft iron animationAn animation that plays by itself on a loop: field between a magnet and soft iron.
- Field patterns between two bar magnets animationAn animation that plays by itself on a loop: field patterns between two bar magnets.
- Forces between two parallel magnets animationAn animation that plays by itself on a loop: forces between two parallel magnets.
- A magnet losing its magnetism animationAn animation that plays by itself on a loop: a magnet losing its magnetism.
- Magnetic induction in a nail animationAn animation that plays by itself on a loop: magnetic induction in a nail.
- Magnetic field around a current-carrying wire animationAn animation that plays by itself on a loop: magnetic field around a current-carrying wire.
- Commutator gaps inside a motor animationAn animation that plays by itself on a loop: commutator gaps inside a motor.
- Right-hand grip rule for a wire animationAn animation that plays by itself on a loop: right-hand grip rule for a wire.
- Dot and cross current in a wire animationAn animation that plays by itself on a loop: dot and cross current in a wire.
- Thicker wire for a stronger electromagnet animationAn animation that plays by itself on a loop: thicker wire for a stronger electromagnet.
- A current-carrying wire between magnet poles animationAn animation that plays by itself on a loop: a current-carrying wire between magnet poles.
- Two parallel cables pushing or pulling animationAn animation that plays by itself on a loop: two parallel cables pushing or pulling.
- Fleming's left-hand rule on a motor animationAn animation that plays by itself on a loop: fleming's left-hand rule on a motor.
- Force on a wire with downward current animationAn animation that plays by itself on a loop: force on a wire with downward current.
- Charged particles bending in a magnetic field animationAn animation that plays by itself on a loop: charged particles bending in a magnetic field.
- An electron beam curving in a magnet animationAn animation that plays by itself on a loop: an electron beam curving in a magnet.
- The coil sides that turn a motor animationAn animation that plays by itself on a loop: the coil sides that turn a motor.
- How a split ring keeps a motor turning animationAn animation that plays by itself on a loop: how a split ring keeps a motor turning.
- A magnet held still inside a coil animationAn animation that plays by itself on a loop: a magnet held still inside a coil.
- A magnet moving into a coil and the meter animationAn animation that plays by itself on a loop: a magnet moving into a coil and the meter.
- A magnet falling slowly through a copper tube animationAn animation that plays by itself on a loop: a magnet falling slowly through a copper tube.
- Slip rings on an a.c. generator animationAn animation that plays by itself on a loop: slip rings on an a.c. generator.
- A generator's voltage through one turn animationAn animation that plays by itself on a loop: a generator's voltage through one turn.
- A generator spinning twice as fast animationAn animation that plays by itself on a loop: a generator spinning twice as fast.
- Finding current from an induced pole animationAn animation that plays by itself on a loop: finding current from an induced pole.
- A magnet approaching a tapped coil animationAn animation that plays by itself on a loop: a magnet approaching a tapped coil.
- One generator turn, one voltage cycle animationAn animation that plays by itself on a loop: one generator turn, one voltage cycle.
- Slip rings and peak voltage animationAn animation that plays by itself on a loop: slip rings and peak voltage.
- Laminated transformer core animationAn animation that plays by itself on a loop: laminated transformer core.
- Transformer turns ratio animationAn animation that plays by itself on a loop: transformer turns ratio.
- Finding a heater's current from its power rating animationAn animation that plays by itself on a loop: finding a heater's current from its power rating.
- What a lamp's power rating means animationAn animation that plays by itself on a loop: what a lamp's power rating means.
- Nichrome element in an oven animationAn animation that plays by itself on a loop: nichrome element in an oven.
- Energy through a resistance animationAn animation that plays by itself on a loop: energy through a resistance.
- Where a battery's power goes animationAn animation that plays by itself on a loop: where a battery's power goes.
- The kilowatt-hour on a home meter animationAn animation that plays by itself on a loop: the kilowatt-hour on a home meter.
- Fuses, breakers, earthing and double insulation animationAn animation that plays by itself on a loop: fuses, breakers, earthing and double insulation.
- Sockets on a household ring circuit animationAn animation that plays by itself on a loop: sockets on a household ring circuit.
- Why wet hands are dangerous animationAn animation that plays by itself on a loop: why wet hands are dangerous.
- Power lost in long cables animationAn animation that plays by itself on a loop: power lost in long cables.
- Wiring a mains plug animationAn animation that plays by itself on a loop: wiring a mains plug.
- Voltages between the mains wires animationAn animation that plays by itself on a loop: voltages between the mains wires.
Chemistry
- Acid–base titration simOpen the burette: pH crawls, leaps at 25.00 cm³, and phenolphthalein turns pink.
- Rate of reaction simWarm the water bath and the gas syringe fills faster, modelled with the Arrhenius equation.
- Testing for cations: NaOH(aq) and NH₃(aq) simCarry a real dropper to eight cation solutions: watch each precipitate form, stay or dissolve in excess, and warm ammonium to turn damp red litmus blue.
- Acid rain simDrag sulfur dioxide and nitrogen dioxide into a cloud and watch the rain's pH fall, a marble statue lose mass and a lake turn acidic; then lime the lake and clean up the air.
- Addition polymerisation simJoin ethene, propene, chloroethene or tetrafluoroethene monomers into a chain, see the bracketed repeat unit with n, and work back from a polymer chain to its monomer.
- Alpha scattering and models of the atom simFire alpha particles at gold foil, count how many go straight through, are deflected or bounce back, turn the detector to count at each angle, and compare the plum-pudding prediction with the nuclear model.
- Choose the separation method simGet a mixture card, drag the right apparatus onto the bench in order, and see whether it works: filtration, evaporation, crystallisation, distillation, fractional distillation, a separating funnel, chromatography, a magnet or sublimation, chosen from the substances' properties.
- Complete and incomplete combustion simChange a Bunsen burner's air hole, pump its gases through a U-tube in ice, limewater and a CO meter, collect soot on a cold dish, and watch a candle under a beaker run out of oxygen.
- Condensation polymers and hydrolysis simPull a nylon thread from between two liquids, build a polyamide or polyester as a water molecule leaves at each link, then break the chain back into monomers by acid hydrolysis.
- Conductivity tester simDip carbon electrodes into solid, molten and dissolved sodium chloride, sugar solution and ethanol, and touch them to graphite, copper and sulfur. A bulb and ammeter show the current; a close-up shows whether ions or electrons are free to move.
- Conservation of mass simWeigh three reactions on a 0.01 g balance: a precipitate in a flask, marble fizzing in acid with the bung in or out, and magnesium burning in a crucible; plot mass against time and explain each change.
- Empirical formula of magnesium oxide simBurn magnesium ribbon in a lidded crucible, weigh to constant mass and work out the formula MgO from your own readings.
- Filtration, evaporation and crystallisation simStir, filter and then evaporate or crystallise to get salt or copper(II) sulfate back out of a mixture with sand, and see how much you recover.
- Flame tests and the spectroscope simClean a nichrome loop in acid, dip it in a solid, hold it in a roaring blue flame, record the colour, name the metal ion and match its line spectrum.
- The greenhouse effect simChange the carbon dioxide and methane in the air (or pick a year from the record), watch infrared being absorbed and sent back down, and read the extra heating and settled temperature; then sort out the ozone-hole mix-up.
- Group 1 metals in water simDrop the same size piece of lithium, sodium or potassium into water with universal indicator: floating, melting, fizzing, the lilac flame, the hydrogen and the pH, with the trend explained. Rubidium and caesium as a clearly marked prediction only.
- The hydrogen–oxygen fuel cell simOpen the hydrogen and oxygen valves of a fuel cell, watch electrons drive a motor and water drip out, read the voltage and current, and compare the fuel cell with a battery and a petrol engine.
- Iron and sulfur: mixture or compound? simPull iron out of an iron and sulfur mixture with a magnet, then heat a fresh mixture until it glows and forms black iron(II) sulfide, which the magnet no longer attracts, and find the fixed proportion from your own masses.
- Making a salt by titration simTitrate with methyl orange, repeat with the same volumes and no indicator, then crystallise sodium chloride, sodium sulfate or the fertiliser ammonium sulfate and work out the yield.
- Making a standard solution and diluting it simWeigh a solid, dissolve it, transfer it with rinsings to a volumetric flask, make up to the mark and invert; then dilute with a pipette. Concentrations in mol/dm³ and g/dm³, and what each slip in technique does to them.
- Which metal oxides can carbon reduce? simHeat the oxides of magnesium, zinc, iron, lead and copper with carbon, in hydrogen, and in competition with other metals. Real data decide each result, and a results table builds the reactivity series and shows why each metal is extracted the way it is.
- Moles of gas from magnesium and acid simWeigh magnesium ribbon, drop it into hydrochloric acid and collect the hydrogen in a gas syringe. Plot the volume against moles of magnesium to measure 24 dm³ per mole, and watch the line level off when the acid runs out.
- Neutralising acid with lime simAdd weighed spatulas of calcium hydroxide or calcium oxide to dilute hydrochloric acid, stir, read the pH meter and plot pH against mass added; then lime a pot of acid soil.
- Preventing rust: barriers and sacrificial protection simEight treated iron nails rust over two weeks: paint, grease, plastic and tin as barriers, zinc and magnesium as sacrificial metals, copper making it worse. Scratch the coats, then protect a buried pipe with a magnesium block.
- Purity from melting and boiling points simMelt four unknown samples in capillary tubes in an oil bath and match them to data cards: pure substances melt sharply, impure ones lower and over a range. Then watch salty water boil above 100 °C and keep rising.
- Reactions of ethene simAdd bromine, hydrogen or steam across the C=C of ethene under the right conditions, name the product, and harden vegetable oil into margarine by adding hydrogen.
- Redox detective simRun six redox reactions, watch the oxidation numbers change and the electrons move, then tag what is oxidised, what is reduced, and the oxidising and reducing agents. All four definitions of redox, checked side by side.
- Water treatment and desalination simDrag a sample of river water through screening, sedimentation, filtration, carbon and chlorination, testing it after each stage; switch stages off to see why each one is there; then desalinate seawater two ways and treat sewage.
- Bioleaching and phytomining simGrow plants on low-grade ore, burn them and dissolve the ash, or let bacteria leach a column of ore week by week, then get the copper out with scrap iron or electrolysis and weigh it.
- Earth's early atmosphere simDrag a timeline from 4.6 billion years ago to today and watch the oceans, algae, plants, limestone and coal appear; once the oceans form, carbon dioxide falls and oxygen rises; record readings and graph them.
- Methane and chlorine in UV light simShine a UV lamp on methane and chlorine in a graduated tube over water: with no UV nothing happens; with it the chlorine fades, oily drops form, the water rises, and CH₃Cl, then CH₂Cl₂, CHCl₃ and CCl₄ build up.
- Nanoparticles: surface area to volume simDrag a slider to cut a cube into smaller and smaller cubes, record the surface area and volume, and plot SA:V against 1/a to see why nanoparticles behave differently.
- Ozone layer and CFCs simOpen a CFC valve under a model atmosphere, let the years pass, and watch chlorine atoms thin the ozone layer and the UV index at the ground climb; then close the valve and see how slowly it recovers.
- Plastic waste and recycling simDrag six plastics to landfill, the sea, an incinerator, a pellet-making machine or a depolymerising reactor, and see what really happens, with the carbon dioxide and hydrogen chloride from burning worked out from balanced equations.
- Transition elements against Group 1 simWeigh cubes of sodium, iron and copper, turn pale green iron(II) yellow-brown with hydrogen peroxide, and time how iron(III) oxide and copper(II) oxide speed up oxygen from hydrogen peroxide while sodium chloride does nothing.
- Indicators and the pH scale simTest eleven real solutions and three mystery tubes with universal indicator, litmus, methyl orange, thymolphthalein, phenolphthalein and a pH meter, and build your own pH scale.
- Acidic, basic and amphoteric oxides simTest ten oxides with water and universal indicator, dilute acid and aqueous alkali, record what you see, and sort each into basic, acidic, amphoteric or neutral.
- Hydrated salts and the tests for water simHeat blue copper(II) sulfate crystals to constant mass, record your own weighings, work out x in CuSO₄·xH₂O, then test four liquids for water and for purity.
- Strong and weak acids simThe student tests hydrochloric and ethanoic acid at the same concentration with a pH meter, a conductivity tester and magnesium ribbon, then dilutes the strong acid tenfold at a time and plots the pH.
- Periodic table explorer simThe student taps elements to see their shells, properties and real look, tests themselves on configuration, group and period, predicts trends down groups and across Period 3, and checks Mendeleev's predictions.
- Reversible reactions and dynamic equilibrium simSqueeze or heat a sealed syringe of NO₂, add acid or alkali to chromate, and run a model contact-process converter, watching the forward and backward rates become equal as the mixture settles.
- Extracting aluminium by electrolysis simThe student runs a cut-away aluminium smelting cell: melts alumina, adds cryolite, switches on the current, waits hour by hour, changes a worn anode, taps the metal and plots the aluminium made.
- Homologous series and isomers builder simBuild molecules atom by atom, check and name them, find every isomer of a formula, test for C=C with bromine water and compare boiling points across five series.
- How much oxygen is in air? simPush 100 cm³ of air back and forth over hot copper between two gas syringes, read the volume after each pass, let it cool and work out that about 21 % of air is oxygen.
- Catalysts and enzymes: decomposing hydrogen peroxide simWeigh a catalyst, add it to hydrogen peroxide, read the gas syringe every 10 s, compare the curves, then filter and reweigh the catalyst and test the gas.
- Thermometric titration simAdd sodium hydroxide to acid in a polystyrene cup a portion at a time, stir, record the temperature, and find the end point and the acid's concentration where two best-fit lines meet.
- Making ammonia simHeat the dry mixture: 2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2NH₃ + 2H₂O.
- Testing for anions simEach tube holds 2.0 cm³ of a 0.1 mol/dm³ solution of one sodium salt; the eighth holds 5 cm³ of limewater.
- The atom builder simProtons (mass 1, charge +1) and neutrons (mass 1, charge 0) sit in the nucleus; electrons (mass 1/1840, charge −1) sit in shells round it.
- The blast furnace simThe zone temperatures are the lesson's (about 700, 900, 1200 and 1900 °C, and iron tapped at about 1500 °C).
- Calorimetry simStart the clock, take readings for 30 s, then the alkali is poured in (or the solid tipped in) and stirred.
- Testing for cations simEach tube holds 2.0 cm³ of a 0.1 mol/dm³ solution of one cation.
- Chromatography simThe solvent (the mobile phase) soaks up the paper (the stationary phase) and carries each dye a fixed share of the way: a dye more soluble in the solvent goes further.
- Collision theory simCaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂.
- Colour tests simEach tube holds 2.0 cm³ and each drop is 0.05 cm³.
- Cracking simCracking breaks long alkane molecules into shorter alkanes and alkenes.
- Diffusion in a liquid simOne crystal of potassium manganate(VII), 0.6 mg, goes into 150 cm³ of still water.
- Diffusion in a gas simAmmonia (Mᵣ 17) diffuses from the left, hydrogen chloride (Mᵣ 36.5) from the right.
- Disappearing cross simMake 50 cm³ of mixture from 0.20 mol/dm³ sodium thiosulfate and water, warm it to the temperature in a water bath, and stand the flask on the card.
- Displacement simA more reactive metal displaces a less reactive metal from a solution of its salt: the less reactive metal coats the piece, and its coloured ions (blu
- Distillation simHeat the flask. When the liquid boils, its vapour rises past the thermometer bulb, which sits level with the side arm so it reads the vapour that is leaving.
- Dot and cross simDots and crosses are only bookkeeping: all electrons are the same, and the two marks show which atom each one came from.
- Drying a gas simA drying agent absorbs water vapour without reacting with the gas itself.
- Electrolysis simThe anode is joined to the positive terminal (red) and attracts anions; the cathode is joined to the negative terminal (black) and attracts cations.
- Electroplating simIn both cells the anode is copper or impure copper, and Cu → Cu²⁺ + 2e⁻ there; at the cathode Cu²⁺ + 2e⁻ → Cu.
- The energy hill simAn energy level diagram shows only two levels, the reactants and the products, and ΔH between them.
- Formulas and equations simFormula: an ionic compound has no overall charge.
- Fermentation simYeast turns glucose into ethanol and carbon dioxide: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂.
- Fractional distillation simCrude oil is heated to about 350 °C and fed in near the bottom of the column, which is hot at the bottom and cool at the top.
- Heat of combustion simWeigh the burner, light it under 100 g of water in the copper can, stir and read the temperature, put it out and weigh it again.
- Cleaning up exhaust gases simCar: the engine is drawn about 43 times slower than at idle.
- Collecting a gas simTwo questions choose the method: is the gas soluble in water, and is it denser or less dense than air (M_r about 29)?
- Rate of reaction sim50 cm³ of hydrochloric acid is in the flask.
- Tests for gases simTest the gas at the mouth of the tube as soon as it is made, because gases escape.
- The Haber process simNitrogen comes from the air (by fractional distillation of liquid air) and hydrogen from natural gas reacted with steam.
- Halogen displacement simEach tube holds 2.0 cm³ of 0.10 mol/dm³ potassium halide, which is colourless.
- Heating carbonates simA metal carbonate breaks up on heating into the metal oxide and carbon dioxide, MCO₃ → MO + CO₂, and the carbon dioxide turns limewater milky.
- Heating nitrates simNitrates split three ways on heating.
- Lab basics simMeasuring and simple separations, the apparatus a chapter 1 step names.
- Loss of mass sim50 cm³ of hydrochloric acid is in the flask on the balance.
- Metals with acid simEach tube holds 10 cm³ of 2.0 mol/dm³ hydrochloric acid.
- Mole calculations simEvery route goes through moles.
- Molten lead(II) bromide simSwitch on first: the solid's ions are held in fixed positions in the lattice, so no current flows and the lamp stays off.
- Reading a meniscus simLiquid in a narrow tube curves: water's meniscus curves down, so read its bottom; mercury's curves up, so read its top.
- The porous pot simGas passes the unglazed pot's wall through its tiny pores, both ways at once.
- Reducing copper(II) oxide simCarbon is above copper in the reactivity series, and so is hydrogen, so each takes the oxygen from heated copper(II) oxide: the oxide is reduced to pi
- Heating under reflux simHeat the flask in the water bath (no flame: ethanol and the ester catch fire easily).
- Rusting simFour identical iron nails, left for a week at room temperature.
- Making a salt simCopper(II) sulfate by the excess-insoluble-solid method.
- Separating funnel simLiquids that do not mix (immiscible) settle into two layers; the denser one forms the lower layer.
- Simple cell simThe more reactive metal loses electrons more easily, so it dissolves and becomes the negative terminal.
- States of matter simSubstance X is the lessons' example, not a real substance: it melts at 45 °C and boils at 130 °C.
- Structures in 3D simEach model is a small piece of a structure that goes on and on in every direction (iodine is a crystal of separate molecules).
- Sublimation simIodine sublimes and sodium chloride does not.
- Solubility and pollutants simSolubility: each cell is worked out from the lesson's rules.
- Acid–alkali titration sim25.0 cm³ of sodium hydroxide was pipetted into the flask with three drops of methyl orange, which is yellow in alkali.
- Identify the salt simBottle X holds a 0.1 mol/dm³ solution of one salt.
- Measuring volumes simPick the volume you need and press Measure it.
- Metals with water and steam simCold water gives the metal hydroxide and hydrogen; steam gives the metal oxide and hydrogen, never the hydroxide, because a hydroxide would lose its w
- Valency from outer electrons, phosphorus to PCl₃ animationAn animation that plays by itself on a loop: valency from outer electrons, phosphorus to PCl₃.
- Polyatomic ions such as sulfate in 3D animationAn animation that plays by itself on a loop: polyatomic ions such as sulfate in 3D.
- Criss-cross formulae: MgO and Al₂(SO₄)₃ animationAn animation that plays by itself on a loop: criss-cross formulae: MgO and Al₂(SO₄)₃.
- Half-equations: electrons gained and lost animationAn animation that plays by itself on a loop: half-equations: electrons gained and lost.
- Balancing ethanol burning in oxygen animationAn animation that plays by itself on a loop: balancing ethanol burning in oxygen.
- Balancing iron oxide with carbon, and making urea animationAn animation that plays by itself on a loop: balancing iron oxide with carbon, and making urea.
- Magnesium and oxygen make magnesium oxide animationAn animation that plays by itself on a loop: magnesium and oxygen make magnesium oxide.
- Valency from a Roman numeral: iron(III) and others animationAn animation that plays by itself on a loop: valency from a Roman numeral: iron(III) and others.
- Naming ionic compounds: CaCl₂, NH₄Cl, KNO₃ animationAn animation that plays by itself on a loop: naming ionic compounds: CaCl₂, NH₄Cl, KNO₃.
- Criss-cross formulae and simplest ratios animationAn animation that plays by itself on a loop: criss-cross formulae and simplest ratios.
- Which product is the precipitate animationAn animation that plays by itself on a loop: which product is the precipitate.
- Word equations to balanced equations animationAn animation that plays by itself on a loop: word equations to balanced equations.
- Groups such as nitrate counted as one animationAn animation that plays by itself on a loop: groups such as nitrate counted as one.
- Acids, water and balancing BaHPO₄ animationAn animation that plays by itself on a loop: acids, water and balancing BaHPO₄.
- Reading a meniscus at eye level animationAn animation that plays by itself on a loop: reading a meniscus at eye level.
- Mass on Earth and the Moon, and units of measure animationAn animation that plays by itself on a loop: mass on Earth and the Moon, and units of measure.
- Paper chromatography: spots rise with the solvent animationAn animation that plays by itself on a loop: paper chromatography: spots rise with the solvent.
- Locating agents reveal invisible spots animationAn animation that plays by itself on a loop: locating agents reveal invisible spots.
- Reading paper chromatograms animationAn animation that plays by itself on a loop: reading paper chromatograms.
- Choosing a separation method animationAn animation that plays by itself on a loop: choosing a separation method.
- Thermometers and measuring instruments animationAn animation that plays by itself on a loop: thermometers and measuring instruments.
- Reading a burette titre animationAn animation that plays by itself on a loop: reading a burette titre.
- Burette and measuring cylinder scales animationAn animation that plays by itself on a loop: burette and measuring cylinder scales.
- Collecting gases animationAn animation that plays by itself on a loop: collecting gases.
- Drying agents for gases animationAn animation that plays by itself on a loop: drying agents for gases.
- Collecting gas by displacement of air animationAn animation that plays by itself on a loop: collecting gas by displacement of air.
- Separating a solid from a liquid animationAn animation that plays by itself on a loop: separating a solid from a liquid.
- Four types of solid structure animationAn animation that plays by itself on a loop: four types of solid structure.
- Elements, compounds and mixtures animationAn animation that plays by itself on a loop: elements, compounds and mixtures.
- Covalent and ionic bonding animationAn animation that plays by itself on a loop: covalent and ionic bonding.
- Counting atoms in a molecule animationAn animation that plays by itself on a loop: counting atoms in a molecule.
- Camphor and iodine: simple molecular solids animationAn animation that plays by itself on a loop: camphor and iodine: simple molecular solids.
- How ions get their charges animationAn animation that plays by itself on a loop: how ions get their charges.
- Diamond and graphite, allotropes of carbon animationAn animation that plays by itself on a loop: diamond and graphite, allotropes of carbon.
- Solubility clues and an ionic solid animationAn animation that plays by itself on a loop: solubility clues and an ionic solid.
- Hydrogens on water, ammonia and methane animationAn animation that plays by itself on a loop: hydrogens on water, ammonia and methane.
- Lewis diagrams of oxygen and carbon animationAn animation that plays by itself on a loop: lewis diagrams of oxygen and carbon.
- Polymer chains and carbon backbones animationAn animation that plays by itself on a loop: polymer chains and carbon backbones.
- Iron, sulfur and iron sulfide melting points animationAn animation that plays by itself on a loop: iron, sulfur and iron sulfide melting points.
- Group 1 atoms: lithium, sodium and potassium animationAn animation that plays by itself on a loop: group 1 atoms: lithium, sodium and potassium.
- Ionic and covalent: sodium chloride and hydrogen chloride animationAn animation that plays by itself on a loop: ionic and covalent: sodium chloride and hydrogen chloride.
- Element boxes with a dash for mass animationAn animation that plays by itself on a loop: element boxes with a dash for mass.
- Group names and shell diagrams animationAn animation that plays by itself on a loop: group names and shell diagrams.
- Metallic character down Group 1 animationAn animation that plays by itself on a loop: metallic character down Group 1.
- The six noble gases animationAn animation that plays by itself on a loop: the six noble gases.
- Group and period from electron shells animationAn animation that plays by itself on a loop: group and period from electron shells.
- Nitrogen's place in the table and ammonia animationAn animation that plays by itself on a loop: nitrogen's place in the table and ammonia.
- Rows of the printed periodic table animationAn animation that plays by itself on a loop: rows of the printed periodic table.
- Element boxes in periods 4 and 5 animationAn animation that plays by itself on a loop: element boxes in periods 4 and 5.
- Lanthanoid and actinoid rows animationAn animation that plays by itself on a loop: lanthanoid and actinoid rows.
Biology
- Light and photosynthesis simMove the lamp: light falls with the inverse square law and the pondweed bubbles slow.
- Enzymes and temperature simSet the water bath and watch iodine spots tell you when the starch is gone.
- Agar cubes: what affects diffusion simCut pink agar cubes with a scalpel, pour hydrochloric acid into a beaker in a water bath, set the temperature and the acid concentration, and drop the cubes in. Each cube clears from the outside in while a stopwatch runs. A results table fills with side, SA, V, SA:V, time to clear and rate 1/t, and your own readings are plotted on a graph.
- Blood glucose control: insulin, glucagon and diabetes simDrag a plate to the mouth, a shoe onto the track or an insulin pen to the arm. Watch the islet's beta and alpha cells release insulin and glucagon, the liver's glycogen store fill and empty, and blood glucose return to normal on a live graph. Switch to type 1 or type 2 diabetes and compare peaks and recovery times in a results table.
- The digestive journey simDrag a meal from the mouth to the rectum. Each region shows its enzymes, its pH and how much starch, protein and fat is left, with live bars, a graph and a results table.
- Enzymes and pH: amylase and starch simPour a pH buffer into a tube of amylase, drag it into a 37 °C water bath, add warm starch and start the stopwatch. Drag the dropping pipette to the spotting tile every 10 s: the iodine stays blue-black until the starch is gone, then stays orange-brown. Fill a results table with pH, time to the end point and rate = 1/t, and plot your own graph of rate against pH.
- The heart and the cardiac cycle simDrag through one heartbeat on a front view of the heart in section. The chambers contract, the four valves open and shut as the pressures cross, and a linked graph shows atrium, ventricle and aorta pressure, with a results table to fill.
- The kidney and the nephron simDrag a drop of filtrate through one nephron, zoomed from the kidney. See what ultrafiltration lets through, what selective reabsorption takes back, and how water, glucose, urea and salts change, with a live concentration graph and a plasma, filtrate and urine table to fill.
- Breathing: the mechanism and a spirometer trace simThe student contracts the diaphragm and intercostal muscles on a model chest to make air flow in and out, then reads tidal volume, vital capacity and breathing rate from a spirometer trace at rest and in exercise.
- Yeast respiration and temperature simSet a water bath, settle a tube of yeast in glucose, count carbon dioxide bubbles three times at each temperature, plot the means to find the optimum and test the gas with limewater.
- ABO blood transfusion: test every pair simDrag donor red cells (A, B, AB, O) from blood bags into wells of recipient plasma on a white typing tile, rock it, see under a hand lens whether the cells clump, and fill all 16 boxes of the donor table.
- Alveolus gas exchange simTurn the knobs on an alveolus teaching model to change breathing, blood flow, wall thickness and altitude, watch oxygen and carbon dioxide cross one alveolus and its capillary, take your own readings and graph them.
- Arteries, veins and capillaries simSlide a stained artery-and-vein section under a microscope to compare the walls, lumens and capillaries at real size, take your own pressure and speed readings along the circuit, and squeeze a vein-valve model to see the valves open and shut.
- Bile and emulsification simAdd bile (or water) to oil, shake and watch the droplets split on a microscope screen, then time lipase turning pink phenolphthalein colourless at 35 °C and plot how the time falls as the surface area grows.
- Blood components and clotting simSteer a stained blood smear under a microscope (×100 to ×1000 with oil) to find and name red cells, phagocytes, lymphocytes, platelets and plasma, then cut a small vessel and step through clotting in the book's order, and read the layers of settled blood.
- Capillary exchange and tissue fluid simPump up the pressure and set the flow on a working capillary model, then watch fluid, oxygen and glucose leave one real capillary and carbon dioxide enter, take your own readings and graph them.
- Coronary heart disease simGrow a fatty plaque in a coronary artery on a heart teaching model with risk-factor sliders, watch blood flow to the heart muscle fall, let a clot cause a heart attack, and drag a catheter to put in a stent.
- Double circulation: follow a red cell simDrag a red bead (one red blood cell) round a classroom double-circulation board through the lungs, heart, liver, gut, kidney or legs, predict each next vessel, read its oxygen saturation and the two pressure gauges, and record and graph the readings.
- Enzyme active site (lock and key) simDrag starch, protein and fat into a model amylase's active site, then heat it or change the pH and watch the active site change shape; run a minute at a time and plot the rate against temperature.
- Exercise, breathing and oxygen debt simSet the load on an exercise bike, count the breaths and read the depth off a spirometer trace, read blood lactic acid, and plot breathing rate and lactic acid against time to see the oxygen debt being repaid after hard exercise.
- Exercise and heart rate: take the pulse simSet the exercise with a metronome on a step, count the pulse for 15 s at the wrist, record resting, straight-after and recovery readings in an empty table, plot them with a best-fit curve, and plan a fair test.
- Inspired and expired air simBreathe in through one tube of limewater and out through the other, watch the cross behind each tube, and find out why only the air you breathe out turns limewater milky.
- Liver and hepatic portal vein simPlay a meal or a fast half an hour at a time, sample the hepatic portal vein and the hepatic vein, and see the liver store glucose as glycogen, release it again, and turn excess amino acids into urea.
- Molecule builder simDrag glucose units into starch, glycogen or cellulose, amino acids into a polypeptide, or glycerol and fatty acids into a fat, count the water each join releases, and split the bonds again by hydrolysis.
- Mystery food bench simRun the iodine, Benedict's, biuret and ethanol emulsion tests on an unknown food, heating the Benedict's tube in a water bath, record each colour in a results table and work out which food it was.
- Peristalsis simContract the circular muscles behind a bolus and the longitudinal muscles in front of it, segment by segment, then turn the oesophagus upright, lying down or upside down and switch gravity off: the food still arrives at the same speed.
- Smoking and the airways simSet how many cigarettes a day, watch tar stop the cilia and mucus build up in the airway, and measure how much haemoglobin carbon monoxide takes away from oxygen.
- Villus absorption simZoom from the gut wall into one villus and two of its cells, turn knobs for the microvilli, the wall's thickness and the blood flow, and run a minute at a time to see glucose and amino acids go into the blood and fats into the lacteal.
- Amylase: test the starch simMix the same volumes of starch and amylase in a controlled water bath.
- Bell jar: pressure and ventilation simPulling the rubber sheet down increases the enclosed space.
- Benedict’s: heat before reading simMix the sample with Benedict’s reagent and heat in a hot water bath before reading.
- Biuret: test for protein simAdd prepared Biuret reagent to the food sample.
- Catalase: collect the oxygen simCatalase breaks down hydrogen peroxide: 2H₂O₂ → 2H₂O + O₂.
- Dialysis: what crosses the membrane? simA bench model compares blood-side solution with dialysis fluid across a partially permeable membrane.
- Ethanol emulsion: test for fat simShake the prepared sample with ethanol, then pour the extract into water.
- Fermenter: grow engineered bacteria simA bench fermenter controls temperature, aeration and nutrient supply while bacteria grow.
- Germination: compare conditions simCompare viable seeds of the same kind over the same period.
- Iodine: test for starch simAdd iodine solution to the prepared food sample.
- Leaf starch test: follow the method simBoil the leaf in water for about 1 minute, then heat it in ethanol in a water bath to remove chlorophyll.
- Limiting factors simThe rate is set by whichever requirement is in shortest supply.
- Microscope: magnification and focus simTotal magnification is eyepiece magnification multiplied by objective magnification.
- Osmosis: watch the level simA sucrose solution is separated from the surrounding solution by a membrane permeable to water but not sucrose.
- Photosynthesis: prove the conditions simStart with destarched plants, expose matched leaves to the chosen conditions, then test both leaves for starch by the same complete iodine method.
- Photosynthesis: collect oxygen from pondweed simPondweed lies under an inverted funnel in water.
- Potato: measure mass change simSoak equal potato strips for the same time, remove them, blot gently and weigh.
- Potometer: water uptake simA potometer measures water uptake, which estimates transpiration.
- Respiration: heat from seeds simCompare equal amounts of germinating seeds and boiled seeds in identical insulated flasks.
- Respiration: follow the carbon dioxide simAir moves from left to right: A removes incoming carbon dioxide with potassium hydroxide, B checks that air with limewater, C holds the seeds, and D t
- Sewage treatment: oxygen and decomposition simThis bench model follows screening, settlement, aerobic treatment of the liquid and anaerobic digestion of sludge.
- Vitamin C: the DCPIP test simPut the same 25.0 cm³ of fresh blue DCPIP in the flask for each trial.
- Visking tubing: starch stays in, iodine gets through animationAn animation that plays by itself on a loop: visking tubing: starch stays in, iodine gets through.
- Plant cell losing water by osmosis in salt animationAn animation that plays by itself on a loop: plant cell losing water by osmosis in salt.
- Boiled plant tissue with broken membranes animationAn animation that plays by itself on a loop: boiled plant tissue with broken membranes.
- Fat vs carbohydrate molecules as fuel animationAn animation that plays by itself on a loop: fat vs carbohydrate molecules as fuel.
- Glycogen: a branched store of glucose units animationAn animation that plays by itself on a loop: glycogen: a branched store of glucose units.
- Egg protein unfolding when heated animationAn animation that plays by itself on a loop: egg protein unfolding when heated.
- Lactase and lactose: lock-and-key fit animationAn animation that plays by itself on a loop: lactase and lactose: lock-and-key fit.
- Pineapple enzyme: cold versus canning heat animationAn animation that plays by itself on a loop: pineapple enzyme: cold versus canning heat.
- Amylase starch test at 30 °C and 40 °C animationAn animation that plays by itself on a loop: amylase starch test at 30 °C and 40 °C.
- Protein digestion: stomach then small intestine animationAn animation that plays by itself on a loop: protein digestion: stomach then small intestine.
- Fibre moving through the gut animationAn animation that plays by itself on a loop: fibre moving through the gut.
- Peristalsis in the oesophagus animationAn animation that plays by itself on a loop: peristalsis in the oesophagus.
- Bile from liver to fat emulsion animationAn animation that plays by itself on a loop: bile from liver to fat emulsion.
- Tadpole and frog gut comparison animationAn animation that plays by itself on a loop: tadpole and frog gut comparison.
- Lipase products turning the indicator animationAn animation that plays by itself on a loop: lipase products turning the indicator.
- Deamination of excess amino acids in the liver animationAn animation that plays by itself on a loop: deamination of excess amino acids in the liver.
- Glucagon: pancreas signal to liver store to blood animationAn animation that plays by itself on a loop: glucagon: pancreas signal to liver store to blood.
- ABO blood groups: red-cell antigens animationAn animation that plays by itself on a loop: aBO blood groups: red-cell antigens.
- Fish single circulation versus double circulation animationAn animation that plays by itself on a loop: fish single circulation versus double circulation.
- Oxygen-rich blood from lungs to heart animationAn animation that plays by itself on a loop: oxygen-rich blood from lungs to heart.
- Skin arterioles widening after exercise animationAn animation that plays by itself on a loop: skin arterioles widening after exercise.
- Capillary cross-sectional area and blood speed animationAn animation that plays by itself on a loop: capillary cross-sectional area and blood speed.
- Absorbed glucose: intestine to liver animationAn animation that plays by itself on a loop: absorbed glucose: intestine to liver.
- Left and right ventricle pressure animationAn animation that plays by itself on a loop: left and right ventricle pressure.
- Heart seen from the front: the person's left and right animationAn animation that plays by itself on a loop: heart seen from the front: the person's left and right.
- Blood crossing a hole between the ventricles animationAn animation that plays by itself on a loop: blood crossing a hole between the ventricles.
- Ventricle ejection while pressure falls animationAn animation that plays by itself on a loop: ventricle ejection while pressure falls.
- Tissue fluid leaving the capillaries animationAn animation that plays by itself on a loop: tissue fluid leaving the capillaries.
- CAM cactus: night-time gas exchange animationAn animation that plays by itself on a loop: cAM cactus: night-time gas exchange.
- Giant waterlily leaf: thin for short diffusion animationAn animation that plays by itself on a loop: giant waterlily leaf: thin for short diffusion.
- Stoma opening: guard cells take in water animationAn animation that plays by itself on a loop: stoma opening: guard cells take in water.
- Light through the leaf epidermis to the palisade animationAn animation that plays by itself on a loop: light through the leaf epidermis to the palisade.
- Limiting factors in photosynthesis animationAn animation that plays by itself on a loop: limiting factors in photosynthesis.
- Pondweed bubbles under a lamp animationAn animation that plays by itself on a loop: pondweed bubbles under a lamp.
- Root hair cell taking up mineral ions animationAn animation that plays by itself on a loop: root hair cell taking up mineral ions.
- Xylem and phloem in fast-growing bamboo animationAn animation that plays by itself on a loop: xylem and phloem in fast-growing bamboo.
- Humidity and the water vapour gradient animationAn animation that plays by itself on a loop: humidity and the water vapour gradient.
- Transpiration pull in a tall redwood animationAn animation that plays by itself on a loop: transpiration pull in a tall redwood.
- Ringing bark: sugar builds up above the ring animationAn animation that plays by itself on a loop: ringing bark: sugar builds up above the ring.
- Bacterial cell structure animationAn animation that plays by itself on a loop: bacterial cell structure.
- Cell differentiation: nerve and muscle cells animationAn animation that plays by itself on a loop: cell differentiation: nerve and muscle cells.
- Cell membrane: diffusion, osmosis and active transport animationAn animation that plays by itself on a loop: cell membrane: diffusion, osmosis and active transport.
- Animal cell bursting in pure water animationAn animation that plays by itself on a loop: animal cell bursting in pure water.
- Sucrose split into two sugars animationAn animation that plays by itself on a loop: sucrose split into two sugars.
- What fats do besides giving energy animationAn animation that plays by itself on a loop: what fats do besides giving energy.
- Glucose built up and broken down animationAn animation that plays by itself on a loop: glucose built up and broken down.
- Enzyme denatured by boiling animationAn animation that plays by itself on a loop: enzyme denatured by boiling.
- Stomach acid and the stomach lining animationAn animation that plays by itself on a loop: stomach acid and the stomach lining.
- Amylase and starch in the acid stomach animationAn animation that plays by itself on a loop: amylase and starch in the acid stomach.
- Fat absorbed into a lacteal, bypassing the liver animationAn animation that plays by itself on a loop: fat absorbed into a lacteal, bypassing the liver.
- Liver regrowth and scarring animationAn animation that plays by itself on a loop: liver regrowth and scarring.
- Starch to maltose to glucose animationAn animation that plays by itself on a loop: starch to maltose to glucose.
- Cell and hormone signalling models animationAn animation that plays by itself on a loop: cell and hormone signalling models.
- Haemoglobin picking up and releasing oxygen animationAn animation that plays by itself on a loop: haemoglobin picking up and releasing oxygen.
- Blood clotting: fibrinogen to fibrin threads animationAn animation that plays by itself on a loop: blood clotting: fibrinogen to fibrin threads.
- High altitude: more red cells over weeks animationAn animation that plays by itself on a loop: high altitude: more red cells over weeks.
- ABO blood donation: who gives and receives animationAn animation that plays by itself on a loop: aBO blood donation: who gives and receives.
- Red cells in single file through a capillary animationAn animation that plays by itself on a loop: red cells in single file through a capillary.
- Heart filling, then contracting animationAn animation that plays by itself on a loop: heart filling, then contracting.
- Coronary bypass around a blockage animationAn animation that plays by itself on a loop: coronary bypass around a blockage.
- Leaky mitral valve animationAn animation that plays by itself on a loop: leaky mitral valve.
- Heart attack: damaged muscle fibres animationAn animation that plays by itself on a loop: heart attack: damaged muscle fibres.
- Atherosclerosis narrowing an artery animationAn animation that plays by itself on a loop: atherosclerosis narrowing an artery.
- Haemoglobin picking up oxygen animationAn animation that plays by itself on a loop: haemoglobin picking up oxygen.
- Leaf cross-section: air spaces and stomata animationAn animation that plays by itself on a loop: leaf cross-section: air spaces and stomata.
- Destarching before the leaf starch test animationAn animation that plays by itself on a loop: destarching before the leaf starch test.
- Plant dry mass after dark animationAn animation that plays by itself on a loop: plant dry mass after dark.
- Water through a root, cell to cell animationAn animation that plays by itself on a loop: water through a root, cell to cell.
- Potometer measuring water uptake animationAn animation that plays by itself on a loop: potometer measuring water uptake.
- Ringing a stem: radioactive tracer in phloem animationAn animation that plays by itself on a loop: ringing a stem: radioactive tracer in phloem.
- Xylem and phloem: two transport tissues animationAn animation that plays by itself on a loop: xylem and phloem: two transport tissues.
- Aerobic respiration animationAn animation that plays by itself on a loop: aerobic respiration.
- Respiration as the oxidation of food animationAn animation that plays by itself on a loop: respiration as the oxidation of food.
- Everything the energy is spent on animationAn animation that plays by itself on a loop: everything the energy is spent on.
- Why one glucose gives two lactic acid molecules animationAn animation that plays by itself on a loop: why one glucose gives two lactic acid molecules.
- What the fast heart rate is actually for animationAn animation that plays by itself on a loop: what the fast heart rate is actually for.
- Showing that respiration releases energy animationAn animation that plays by itself on a loop: showing that respiration releases energy.
- Showing that respiration gives off carbon dioxide animationAn animation that plays by itself on a loop: showing that respiration gives off carbon dioxide.
- Showing that fermentation gives off carbon dioxide animationAn animation that plays by itself on a loop: showing that fermentation gives off carbon dioxide.
- The breathing system and gaseous exchange animationAn animation that plays by itself on a loop: the breathing system and gaseous exchange.
- What gas exchange means animationAn animation that plays by itself on a loop: what gas exchange means.
- Seven stages from nostril to alveolus animationAn animation that plays by itself on a loop: seven stages from nostril to alveolus.
- The nose, and the rings that are not rings animationAn animation that plays by itself on a loop: the nose, and the rings that are not rings.
- Oxyhaemoglobin comes apart again animationAn animation that plays by itself on a loop: oxyhaemoglobin comes apart again.
- Plant structures that clone themselves animationAn animation that plays by itself on a loop: plant structures that clone themselves.
- Reproduction in flowering plants animationAn animation that plays by itself on a loop: reproduction in flowering plants.
- Every part of the flower, and the job that earns the mark animationAn animation that plays by itself on a loop: every part of the flower, and the job that earns the mark.
- After fertilisation, and where haploid lives in a plant animationAn animation that plays by itself on a loop: after fertilisation, and where haploid lives in a plant.
- The human reproductive systems animationAn animation that plays by itself on a loop: the human reproductive systems.
- The male organs, part by part animationAn animation that plays by itself on a loop: the male organs, part by part.
- The female organs, part by part animationAn animation that plays by itself on a loop: the female organs, part by part.
- A sperm cell and an egg cell, row by row animationAn animation that plays by itself on a loop: a sperm cell and an egg cell, row by row.
- The menstrual cycle: length, what is shed, and what disturbs it animationAn animation that plays by itself on a loop: the menstrual cycle: length, what is shed, and what disturbs it.
- The fertile period, and the hormones day by day animationAn animation that plays by itself on a loop: the fertile period, and the hormones day by day.
- Two umbilical arteries, one vein animationAn animation that plays by itself on a loop: two umbilical arteries, one vein.
- Across the placenta: the barrier, the hormones and the faults animationAn animation that plays by itself on a loop: across the placenta: the barrier, the hormones and the faults.
- The endocrine glands and what each hormone does animationAn animation that plays by itself on a loop: the endocrine glands and what each hormone does.
- Blood glucose and diabetes animationAn animation that plays by itself on a loop: blood glucose and diabetes.
- The often-missed diabetes sign: slow wound healing animationAn animation that plays by itself on a loop: the often-missed diabetes sign: slow wound healing.
- Reading three relative traces after a meal animationAn animation that plays by itself on a loop: reading three relative traces after a meal.
- The skin and temperature control animationAn animation that plays by itself on a loop: the skin and temperature control.
- The skin, part by part animationAn animation that plays by itself on a loop: the skin, part by part.
- Where body heat comes from and goes animationAn animation that plays by itself on a loop: where body heat comes from and goes.
- Why a homeostasis feedback diagram loops back animationAn animation that plays by itself on a loop: why a homeostasis feedback diagram loops back.
- A nerve, a neurone and a nerve fibre animationAn animation that plays by itself on a loop: a nerve, a neurone and a nerve fibre.
- Identify the sensory neurone from its cell body and connections animationAn animation that plays by itself on a loop: identify the sensory neurone from its cell body and connections.
- The sensory pathway ends at the brain animationAn animation that plays by itself on a loop: the sensory pathway ends at the brain.
- A reflex blink uses the brain; hand withdrawal uses the spinal cord animationAn animation that plays by itself on a loop: a reflex blink uses the brain; hand withdrawal uses the spinal cord.
- Gene, allele, genotype and phenotype in pea plants animationAn animation that plays by itself on a loop: gene, allele, genotype and phenotype in pea plants.
- Seed colour is the characteristic; yellow and green are variants animationAn animation that plays by itself on a loop: seed colour is the characteristic; yellow and green are variants.
- Meiosis separates the pair; each gamete carries one allele animationAn animation that plays by itself on a loop: meiosis separates the pair; each gamete carries one allele.
- AB shows both antigen effects; pink is an intermediate flower colour animationAn animation that plays by itself on a loop: aB shows both antigen effects; pink is an intermediate flower colour.
- A one-to-two-to-one ratio has four equal parts animationAn animation that plays by itself on a loop: a one-to-two-to-one ratio has four equal parts.
- The sperm supplies the X-or-Y difference in the usual chromosome model animationAn animation that plays by itself on a loop: the sperm supplies the X-or-Y difference in the usual chromosome model.
- Read the parents and the pedigree model before inferring inheritance animationAn animation that plays by itself on a loop: read the parents and the pedigree model before inferring inheritance.
- Height: small genetic effects combine, with the environment animationAn animation that plays by itself on a loop: height: small genetic effects combine, with the environment.
- Mutation: gene sequence, chromosome structure or number animationAn animation that plays by itself on a loop: mutation: gene sequence, chromosome structure or number.
- Albinism: gene variants, melanin and recessive inheritance animationAn animation that plays by itself on a loop: albinism: gene variants, melanin and recessive inheritance.
- One DNA base changes haemoglobin: GAG to GTG animationAn animation that plays by itself on a loop: one DNA base changes haemoglobin: GAG to GTG.
- Chromosome21: follow both products and the two-plus-one result animationAn animation that plays by itself on a loop: chromosome21: follow both products and the two-plus-one result.