The chart recorder sim
The trolley's cord loop turns a 72 mm pulley at the end of the track.
The chart recorder · covers the GCSE, IGCSE, O-Level topic
What the sim shows
The trolley's cord loop turns a 72 mm pulley at the end of the track. A 24 mm pulley on the same shaft winds the pen's cord, so the pen rises a third as far as the trolley moves from the origin O. The paper moves left at a steady 60 mm/s, so distance along the paper is time. The pen therefore draws the displacement-time graph: its height is the displacement and its gradient is the velocity. Below, the chart is laid flat; the dashed triangle shows rise over run. Drag the trolley to draw your own.
- Pen and trace: displacement against time
- Gradient triangle: rise ÷ run = velocity
Use it in your lessons
- Try it here: anyone can unlock 2 figures free, and a free account unlocks up to 5. Runs on a laptop, a Chromebook or a phone; nothing to install.
- Present it and share student links with the teacher plan, from US$5 a month, billed yearly.
- Put it on your own website or LMS for US$9, paid once, or every sim from US$29 a month.
Free guide: 12 practicals as sims, and how to run one in a lesson →
Need a version for your exact set-up? Have one made: US$49 a figure in an order of 5.
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- 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.