Light Microscope

Key Stage 2

A picture of a microscope.

A microscope is piece of equipment used to make small objects appear larger.

Microscopes can be used to see things too small for our eyes to see.

Micro means 'small' and scope means 'small'.

A microscope is piece of equipment used to make small objects appear larger.

Microscopes use convex lenses to magnify an image.

The parts of the microscope are shown in the diagram below:

Eyepiece Lens - This is the lens that you look down.
Coarse Focussing Wheel - This moves the stage by a large amount to bring the image into focus (make the image clear and not blurry).
Fine Focussing Wheel - This moves the stage by a small amount to focus the image carefully (make the image clear and not blurry).
Objective Lens - This is the lens next to the specimen that magnifies the image.
Stage - This where the sample is placed.
Light Source - This can be a lamp or a mirror used to shine light through the specimen.

To see an object clearly with a microscope a specimen must be prepared first.

1. A small specimen is placed on a glass slide.

2. A dye is used to colour the specimen so it can be seen more easily under the microscope.

3. A cover slip is placed on the specimen to flatten it.

4. Tissue is used to absorb any excess dye.

5. The glass slide is placed on the microscope stage.

A light microscope is a device used to observe small objects using visible light.

A light microscope cannot be used to view anything smaller than about 0.2 micrometres.

Light microscopes can be used to view objects as small as bacteria but cannot be used to view viruses.

Image Size = Object Size X Magnification \[Magnification = \tfract{ImageSize}{ObjectSize}\]