Levels of organisation zoom sim
Drag the zoom slider on the bench to fly smoothly from an organelle to a cell, a tissue, an organ, an organ system and the whole organism, for a leaf or a stomach, with the real field of view and a scale bar at every stop, then sort example cards onto the right level and see why each one belongs there.
Cells · covers the O-Level, IGCSE, GCSE topic
What the sim shows
Living things are built in levels. An organelle is a structure inside a cell with a job. A cell is the basic unit of life. A tissue is a group of similar cells doing the same job. An organ is several different tissues working together to carry out a particular function. An organ system is several organs with related functions working together, and an organism is a whole living thing, made of organ systems working together. The close-up follows two real chains. Plant: chloroplast (10 µm), ×15 → palisade mesophyll cell (150 µm), ×2 → palisade mesophyll (300 µm), ×400 → leaf (12 cm), ×4.17 → shoot system (50 cm), ×1.6 → bean plant (80 cm). Animal: mitochondrion (4 µm), ×12.5 → stomach epithelial cell (50 µm), ×3 → epithelium (150 µm), ×2000 → stomach (30 cm), ×4 → digestive system (1.2 m), ×2.5 → human (3 m). Each number is the width of the close-up's field of view, and each × is how many times wider the field gets at that step, so the steps are not equal: the biggest jump is from tissue to organ. Every picture is drawn at its real size for its field (scale = 208 drawing units ÷ field), so the chloroplast really is half the width of a 10 µm field, and the stomach really is two thirds of a 30 cm field. The magnification readout treats the close-up as if it were printed 10 cm wide: magnification = image size ÷ actual size, with 1 mm = 1000 µm and 1 cm = 10 000 µm. Between stops the zoom is smooth on a log scale (each equal drag multiplies the field by the same amount), and the dashed red box in each picture marks the field of the level below. Idealised on purpose: organelles at the first level need an electron microscope to show their detail; the cell, tissue and organ pictures are diagrams in true proportion, not micrographs; the digestive system is shown in a front view with the organs simplified (the stomach is on the body's left, the right of the page). Each drag stop or key press is one step; nothing changes on its own.
- The zoom slider: six stops, from organelle (left) to organism (right)
- The close-up: drawn at real size for its field of view, with a scale bar
- Dashed red box: the field of view of the level below
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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