Practical skills

Question 1

Standard deviation

Answer 1

The standard deviation tells you how much the values in a single sample vary. It’s a measure of the spread of values about the mean.

Question 2

Units

Answer 2

1cm = 10mm
There are 1000 millimeters in 1 meter (1000mm = 1m)
There are 1000 micrometers in 1 millimeter (1000um = 1mm)
There are 1000 nanometers in 1 micrometer (1000nm in 1um)

Question 3

Magnification calculation formula

Answer 3

magnification = image size/real size

Question 4

% Change formula

Answer 4

((Final value - initial value) / initial value) x 100

Question 5

Using Light microscopes

Answer 5

Clip the prepared microscope slide onto the stage.
Select the objective lens with the lowest power.
Use the coarse focus to bring the stage just below the objective lens.
Look down the eyepiece and use the coarse focus to move the stage downwards until the image is roughly in focus.
Use the fine focus to make the image clearer.
If a higher magnification is needed, swap to a more powerful objective lens and refocus.