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How to See Bacteria With a Microscope

Bacteria are almost everywhere, including on your hands, in your stomach, on the computer you're using, in your fridge and even in the most extreme habitats on Earth, such as ocean vents. Although you can't see these tiny organisms with the naked eye, you can see even the smallest types of bacteria under a fairly basic light microscope. Examining bacteria with a microscope is a simple project that does not require special expertise.

Things You'll Need

Microscope
Prepared slide of stained bacteria
40x objective lens
100x objective lens
Pipette
Immersion oil
Lens paper

Instructions

- 1
  Attach both the objective lenses if not already in position. Adjust the microscope so you are using the 40x lens.
- 2
  Position the slide on the microscope stage.
- 3
  Move the slide around until you locate the stain through the eyepiece. Focus on the stain using the focus knobs, although you probably won't be able to see individual bacteria yet.
- 4
  Rotate the lens turret to swing the 40x lens carefully out of the way, without touching the slide. Don't move the 100x lens in yet. The stage should be under the mid-point of the two lenses.
- 5
  Place one drop of immersion oil where you saw the stain.
- 6
  Move the 100x lens into position and focus carefully with the fine focus knob.
- 7
  Move the slide as necessary to find the bacteria within the stain. You may need to slightly adjust the focus.
- 8
  Remove the slide and wipe the lens clean.

Nature