Key points
- All living organisms are made up of cells.
- Cells are the smallest part of a living organism and are around 0.01 mm - 0.03 mm long.
- To look at a cell close up a microscope needs to be used.
Game - onion cells
Play an Atomic Labs activity to look at onion cells under a microscope.
You can also play the full game
Video - Observing cells with a microscope
Step by step
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Try the experiment online
Try out this experiment in Atomic Labs. Go to the Biology lab and try the Investigating onion cells experiment.
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Try out practical experiments in this KS3 science game
How to use a microscope
Move the stage (the flat ledge the slide sits on) down to its lowest position.
Place the glass slide onto the stage. Be careful pushing it under the clips that the cover slide doesn't move or crack.
Select the lowest power objective lens.
Turn the coarse focus knob slowly until you are able to see the cells.
Turn the fine focus knob slowly until the cells are in focus and you can see them clearly.
Repeat steps 1-5 using the higher power magnification to see the cells in more detail.
Calculating magnification
To see an object, the eye piece lens and the objective lens magnification are multiplied together to give the total magnification.
Total magnification = eye piece lens magnification 脳 objective lens magnification
For example: 10 脳 20 = 200
Magnification = 200
Teaching resources
Are you a biology teacher looking for more resources? This series of short films examines the human body through spectacular graphics based on the latest science and stories of remarkable people around the world.
成人快手 Teach has thousands of free, curriculum-linked resources to help deliver lessons - all arranged by subject and age group.
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Try out practical experiments in this KS3 science game.
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