3 - More on Microscopy

Question 1

This is a practical so you will need this.

Answer 1

There will be lots of steps to this so remember!

Question 2

What is a slide?

Answer 2

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

Question 3

How do you prepare a slide to view onion cells?

Answer 3

1) Add a drop of water to the middle of a clean slide
2) Cut up an onion and separate it out 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 - Iodine solution is a stain - Stains are used to highlight objects in a cell by adding colour to them
5) Place a cover slip on top.

Question 4

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

Answer 4

1) Put the slide on the stage
2) Select the lowest powered objective lens
3) Use the coarse adjustment knob to move the stage up just below the lens
4) Look down the eyepiece. Use the adjustment knob to move the stage downwards until the image is in focus.
5) Adjust the focus with the fine adjustment knob until there is a clear image.