Microscope use

Question 1

what are ocular lenses? how much do they magnify?

Answer 1

magnify specimens 10x; lenses you look through

Question 2

what is the revolving nose piece?

Answer 2

disc above objective lenses that allows the user to change lenses

Question 3

what are the objective lenses?

Answer 3

lenses that magnify specimens 4x, 10x, or 40x

Question 4

what is the slide carrier, where is it located, how is it moved?

Answer 4

• located on stage
• for holding slides in place
• movable using knobs at the side of the stage

Question 5

what is the condenser, how do you move it?

Answer 5

• focuses light into a narrow beam that is directed onto the specimen
• raise/lower condenser with Condenser adjustment knob

Question 6

what does the iris diaphragm control, where is located, how is it moved?

Answer 6

• controls contrast
• located under condenser
• movable by handle/dial

Question 7

what are the coarse and fine focus knobs?

Answer 7

• Coarse focus knob → larger of two knobs; visibly moves stage up and down. Used on 4x and 10x, but never 40x
• Fine focus knob → smaller of the two knobs; also moves stage, but almost imperceptibly

Question 8

what is the illuminator, how is it controlled?

Answer 8

-where light exits the bottom of the microscope; controlled by transformer control knob

Question 9

what is a microscope used for?

Answer 9

The microscope is a tool used to view the structure and subcellular structure of cells, singly or in tissues

Question 10

how is total microscope magnification calculated? what is the total microscope magnification at low, medium, and high magnification?

Answer 10

• calculated by multiplying the magnifying power of the objective lens and the ocular lens
• The ocular lens (eyepiece) magnification is 10x
• The objective lens are 4x, 10x, and 40x
• Total magnification of low lens power → 10x X 4x = 40x
• Total magnification of medium lens power → 10x X 10x = 100x
• Total magnification of high lens power → 10x X 40x = 400x

Question 11

what is field of view? what happens to field of view when switching from low power to high power?

Answer 11

• the circular area of the slide that is visible through the eyepieces
• gets smaller when you switch from a lower power to a higher power

Question 12

how do you calculate the actual size of something in the field of view?

Answer 12

field of view (mm)
/
amount of times a specimen would fit length wise in the field of view
eg. high power (40x) –> field of view is 0.40 mm, item could fit 15 times
0.40/15 = 0.027mm

Question 13

how do you show actual size on a drawing?

Answer 13

• add the calculation for actual size (estimated)
• as well as a scale bar beside the length of cell which is labelled
• add total magnification = (40x, 100x, 400x)

Question 14

what 4 things does a figure caption need to include?

Answer 14

1. Type of figure → drawing, graph, diagram etc
2. What the figure is → cell, cross section, tissue, or organism
3. Scientific name
4. Features of significance with reference to labels
   - Eg. Figure 1. Drawing of a cell from Vallisneria sp. (eelgrass) showing cellular detail.

Question 15

what are the 3 steps in making a wet mount?

Answer 15

1. Place a single drop of water in the centre of microscope slide
2. Add specimen
3. Add coverslip by placing one edge of the coverslip at the edge of the water drop and gently lowering

Question 16

what are some key characteristics of plant cells?

Answer 16

• Rectangular/squareish
• Cell wall
• Chloroplasts
• Larger than animal cells
• often green

Question 17

what are some key characteristics of animal cells?

Answer 17

• Roundish
• No cell wall
• No chloroplasts
• Smaller than animals
• can sometimes see nucleus