More on Microscopy

Question 1

What is a slide?

Answer 1

A slide is a strip of clear glass or plastic onto which the specimen is mounted.

Question 2

How do you prepare your slide to view onion cells?

Answer 2

1) Add a drop of water to the middle of a clean slide.
2) Cut up an onion and separate it into layers - use tweezers to peel off some epidermal tissue from the bottom of one of the layers.
3) Using the tweezers place the epidermal tissue into the water on the slide.
4) Add a drop of iodine solution - it is a stain - it is used to highlight objects in a cell by adding colour to them.
5) Place a cover slip on top by standing it upright on the slide next to the water droplet - then tilt and lower it so it covers the specimen.

Question 3

What can happen when placing your cover slip?

Answer 3

You can get air bubbles under there which will obstruct your view of the specimen.

Question 4

What does the lowest-powered objective lens do?

Answer 4

It produces the lowest magnification.

Question 5

What does the coarse adjustment knob do?

Answer 5

You use it to move the stage to and from the lens.

Question 6

What does the fine adjustment knob do?

Answer 6

It adjusts the focus.

Question 7

What do you do if you want to see a slide with greater magnification?

Answer 7

You use the higher-powered objective lens.

Question 8

How do you use a light microscope to look at your slide?

Answer 8

1) Put the slide on the stage
2) Select the lowest-powered objective.
3) Use the coarse adjustment knob to move the stage up.
4) Look at the eyepiece and use the coarse adjustment knob to move the stage downwards until the image is in focus.
5) Adjust the focus with the fine adjustment knob until you get a clear image of what is on the slide.

Question 9

What is the formula for the magnification of your drawing?

Answer 9

Magnification = length of drawing of cell/ real length of cell