Introduction to Microscopes

On Your Lab Handout…

• Read the section titled “History and Importance of Microscopes”.

• Answer the questions that follow.

How to Properly Carry a Microscope

• You will be graded on this!• WALK slowly.• Hold the microscope at 2 points

– One hand on the arm of the microscope– One hand underneath the base

How to Properly Carry a Microscope

BaseBase

ArmArm

Identify Microscope Parts and What They Do

• CAREFULLY go over the microscope and identify the parts.

• You may move the parts GENTLY in order to figure out what the function of each part is.

• Fill in the table below with this information.

1. According to the data presented for Hive 3, the percentage of time spent by the worker bees tending the hive was approximately:

A. 10%B. 15%C. 20%D. 35%

2. According to the figures, what is the relationship between the weight of the individual worker bees and the amount of time spent flying?

A. The lighter the bee, the more time spent flying.

B. The heavier the bee, the more time spent flying.

C. Lighter bees are faster, so less time is spent flying.

D. Heavier bees are faster, so less time is spent flying.

Identify the Parts

Letter Name FunctionA Objective Lens Magnifies, Can Rotate to

Increase/Decrease Magnification

B Stage Clips Keep slide in placeC Diaphragm Adjust the amount of

light that goes through your object of study

D Light Source Provides the light needed to see

E Ocular Lens / Eye Piece

Magnifies, Part that you look through

Letter Name FunctionF Arm Supports the lenses, used to

carry the microscope

G Stage Holds the slide, moves up and down to help focus

H Course Adjustment Knob

Moves the stage up and down to focus the image (low power)

I Fine Adjustment Knob

Helps focus on higher powers

J Base Supports the entire microscope, used to carry the microscope

How to Store a Microscope

• Remove any slides from the microscope• Move the objective lens to the lowest power. • Move the stage as far down as it can go.• Carrying it properly, return it to its spot.• Coil cord and replace cover.

Calculating Magnification

• To calculate the total magnification using a compound light microscope, you must always multiply the power of the ocular lens by the power of the objective lens.

• Total Magnification = Ocular Lens Power x Objective Lens Power

Sample Problem #1

• Jared’s microscope has an ocular lens power of 20. He sets his objective lens power to 10. What will be the total magnification of the object he is observing?

• Ocular lens = 20• Objective lens = 10• Total Magnification = 20 x 10 = 200

Sample Problem #2

• Shelley’s ocular lens has a power of 50. She is looking at a cell under an objective lens of 20. What will be the total magnification of the object she is looking at?

Sample Problem #2

• Shelley’s ocular lens has a power of 50. She is looking at a cell under an objective lens of 20. What will be the total magnification of the object she is looking at?

• Ocular = 50, Objective = 20• Total Magnification = 50 x 20 = 1000