How to observe cells under a microscope

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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.

Video - Observing cells with a microscope

Find out how to observe cells under a microscope

Step by step

A picture showing a microscope an onion and glass slides.

Click to see a step-by-step slideshow.

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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.

Game - Atomic Labs

How to use a microscope

  1. Move the stage (the flat ledge the slide sits on) down to its lowest position.

  2. Place the glass slide onto the stage. Be careful pushing it under the clips that the cover slide doesn't move or crack.

  3. Select the lowest power objective lens.

  4. Turn the coarse focus knob slowly until you are able to see the cells.

  5. Turn the fine focus knob slowly until the cells are in focus and you can see them clearly.

  6. 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 × objective lens magnification

For example: 10 × 20 = 200

Magnification = 200