1.6 Core practical: Investigating Biological Specimens

Question 1

What is the function of eyepiece?

Answer 1

The part of a microscope that we look through to view specimens

Question 2

What is the function of the barrel?

Answer 2

The upper part of a microscope that can be moved up or down to focus the image

Question 3

What is the function of the turret?

Answer 3

The part of the microscope that is rotated to change the magnification lens in use

Question 4

What is the function of the lens?

Answer 4

The lens increases the magnification of the specimen

Question 5

What is the function of the stage?

Answer 5

The flat surface where you place the specimen

Question 6

How do you use a light microscope?

Answer 6

1- Place the slide on the stage and look through the eyepiece lens.

2- Turn the focus wheel to obtain a clear image.

3- Start with the lowest objective lens magnification.

4- Increase the magnification of the objective lens and refocus.

Question 7

How do you prepare a slide (before using a light microscope)?

Answer 7

1- Take a thin layer of the cells from your sample by peeling it off.

2- Add a small amount of the correct chemical stain (to make some parts of the specimen more visible when you look at them through a microscope).

3- Apply the cells to your glass slide by placing them on it.

4- Carefully lower a coverslip onto your slide, taking care to avoid air bubbles

Question 8

How do you calculate magnification?

Answer 8

magnification = image size / actual size of specimen

Question 9

How do you calculate actual size?

Answer 9

actual size = image size / magnification

Question 10

How do you calculate total magnification?

Answer 10

total magnification = objective lens magnification X eyepiece lens magnification