Microscopes

Question 1

What are the steps for preparing a slide? (5)

Answer 1

• Take a clean slide and use a pipette to put one drop of water or mountant in the middle of it - this will secure the specimen in place
• Use tweezers to place your specimen on the slide
• Add a drop of stain if your specimen is completely transparent and colourless - this will make the specimen easier to see. Different stains are used to highlight different structures
• Place a cover slip at one end of the specimen, holding it at an angle with a mounted needle
• Carefully lower the cover slip onto the slide. Press it down gently with the needle so that no air bubbles are trapped under it

Question 2

How do you look at the specimen though the microscope lens? (5)

Answer 2

• Clip the prepared slide onto the stage of the microscope
• Select the lowest-powered objective lens
• Use the coarse adjustment knob to move the stage up so that the slide is just underneath the objective lens. Then, looking down the eyepiece, move the stage downwards until the specimen is nearly in focus
• Then adjust the focus with the fine adjustment knob, until you get a clear image
• If you need to see your specimen with greater magnification swap to a higher-powered objective lens and refocus

Question 3

How do we calculate the total magnification?

Answer 3

You multiply the magnification of the eyepiece lens by the magnification of the objective lens