Microscopy

Question 0

A microscope

Answer 0

An instrument used to see objects too small to be seen with the naked eye

Question 1

Role of Jansen and his son in developing the microscope (1590)

Answer 1

• Lenses placed in a tube
• Forerunner of the compound microscope

Question 2

Role of Hooke in microscopy (1665)

Answer 2

• Observed cork compartments
• He named them ‘cells’

Question 3

Role of van Leeuwenhoek in microscopy (1674)

Answer 3

• Simple microscopes with improved lenses (270x)
• Studied blood, yeast, insects etc.
• First to describe bacteria

Question 4

Role of Schwann, Schleiden and Virchow in developing microscopy (1839)

(Grade 10 only)

Answer 4

Formulated the cell theory

Question 5

Cell theory

(Grade 10 only)

Answer 5

• All living organisms are made up of cells
• the cell is the basic and smallest unit of life
• All cells develop from already existing cells

Modern additions:

• Energy flows inside cells
• DNA is passed on from cell to cell and instructs all cell activity
• All cells have the same basic chemical composition

Question 6

Maximum magnification of a light microscope

Answer 6

1250-1500x

Question 7

Role of Knott and Ruska in microscopy (1931)

Answer 7

• Developed the first electron microscope
• these can today magnify up to about 1 000 000x

Question 8

Microscope tube

Answer 8

Part in which the eyepiece fits

Question 9

Microscope eyepiece

Answer 9

The upper lens of the microscope for magnification (usually 10x)

Question 10

Microscope objective

Answer 10

• Lower lens that is movable
• Objects can be studied with different magnifications
• e.g. 4X, 10X and 40X

Question 11

Microscope nose piece

Answer 11

Part of the microscope that carries the objectives

Question 12

Microscope clip

Answer 12

Keeps slides in position on the stage

Question 13

Microscope arm

Answer 13

Handle of the microscope

Question 14

Microscope coarse adjustment knob

Answer 14

• Moves the stage/tube with large movements to bring the object into focus
• Only used with the low power objective lens

Question 15

Microscope fine adjustment knob

Answer 15

Moves the tube/stage with fine movements for final focus

Question 16

Microscope light source

Answer 16

• Provides light that shines through the opening as well as the mounted object to the eye
• Can be electric or from the sun using a mirror

Question 17

Microscope mirror

Answer 17

In some microscopes it reflects light from the sun

Question 18

Microscope condenser

Answer 18

Concentrates rays of light from the light source onto the object

Question 19

Microscope diaphragm

Answer 19

• Regulates the amount of light that shines onto the object
• Can open and close like the eyes iris

Question 20

How to calculate total magnification

Answer 20

Eye piece magnification X the objective magnification

E.g. 10 X 40 = 400x

Question 21

Some ways to take care of a microscope

Answer 21

• Hold it by the arm and base when carrying
• Never touch lenses
• Always start with smallest objective lens
• Cover the microscope to protect from dust
• Place on a firm, dry surface

Question 22

Preparing a wet mount slide

Answer 22

• Place the specimen on the slide with a drop of water
• cover it with a coverslip
• Draw stain under the coverslip using tissue on the other side of the coverslip
• Dry the surface of the slide

Question 23

Using a microscope

Answer 23

1. Turn on light
2. Set lowest power objective
3. Place slide on stage
4. Centre the specimen in the light
5. Focus using coarse adjustment
6. Adjust light using diaphragm and condenser to sharpest
7. Move to a larger lens
8. Adjust focus using the fine adjustment only

Question 25

Formula to calculate actual size of specimen (Grade 10 only)

Answer 25

Question 26

Formula to calculate magnification using a scale bar (Grade 10 only)

Answer 26