Lab #1: Tools

Question 1

2 main types of microscopes in biology labs

Answer 1

1) Compound Light Microscope
2) Dissection (stereoscopic) Microscope

Question 2

Compound Light Microscope allows for…

Answer 2

View of objects as small as 1 micrometer (um) = 100nm

Question 3

Compound light microscope has 3 main types of lenses

Answer 3

To magnify:
1) Ocular lens
2) Objective lenses

To illuminate:
3) Condenser Lens

Question 4

Where is the ocular lens located?

Answer 4

In the eyepiece

Question 5

What is the typical magnification of the ocular lens?

Answer 5

10X

Question 6

What are the different magnifications of the objective lenses?

Answer 6

4X, 10X, 40X, 100X

Question 7

Total magnification is calculated by…

Answer 7

Multiplying the ocular lens magnification by the objective lens magnification

Question 8

How to know if the condenser is not properly focused

Answer 8

If you see a pattern of circles across the entire field of view

–> usually means the condenser is too high (close to the slide)

Question 9

Purpose of the Diopter Ring

Answer 9

To help focus the eyepiece for different peoples’ eyes

Question 10

How to use the diopter ring

Answer 10

1) Close your left eye and look into the microscope with the right eye only

2) Focus the image with the fine adjustment knob until it is in focus for your right eye

3) Close your right eye and look into the microscope with just your left eye

4) Use the diopter ring to bring the image into focus for your left eye

Question 11

X and Y stage control knobs

Answer 11

Used to move the stage around while the slide is in place

Question 12

Interpupillary distance adjustment

Answer 12

Allows you to adjust the distance between the two eyepieces to match the distance between your own eyes

Question 13

How do you know that the Inter-pupillary distance is set properly for you?

Answer 13

When you look through both eyes and see one big, continuous circular image

Question 14

Process for properly magnifying the image of a specimen

Answer 14

1) Place the specimen over the middle hole in the stage

2) Start with the 4X objective in place and look at the microscope from the SIDE: Using the coarse adjustment knob, put the stage all the way up (should never touch the lens)

3) Get this level into focus and then move onto the 10X level and focus again (using both coarse and fine knobs)

2) Repeat the same process for the 40X and 100X EXCEPT DO NOT USE THE COARSE ADJUSTMENT KNOB for these magnifications

Question 15

What is image inversion in a compound light microscope?

Answer 15

The image you view is inverted and reflected by the different lenses

Question 16

Purpose of a Dissecting Microscope

Answer 16

Allows you to examine opaque objects that are too large or thick to see with a light microscope

Question 17

2 main parts of a dissecting microscope

Answer 17

1) The scope itself
2) The illuminator (light source)