Objective Lens Slide Microscope Structure Lab – Biology

Objective Lens Slide Microscope Structure Lab

In this lab, we learn and experiment with microscopes and study the different parts and functions of a microscope including eyepiece or ocular, nose-piece, objective lens, slide, base, control knob, stage and many more.


Microscope Lab

Label parts of a Microscope:

Microscope structure, Objective lens slide. quiztutors.com

A = Eyepiece/ Ocular                      I = Base

B = Nosepiece                                     J =  Stage Control Knob

C = Objective                                      K = Light Intensity Knob

D = Stage Clips                                   L = Coarse Adjustment Knob

E = Iris Diaphragm                            M = Fine Adjustment Knob

F = Condenser                                     N = On/Off Switch

G = Stage                                             0 = Arm

H = Illuminator/Light Source


DATA Collection –MicroscopySince you are not observing specimens under the microscope, just fill in the calculations for total magnification using the different objective lens. Remember total magnification = ocular lens magnification (always 10X) times objective lens magnification!

 A) With the 4X objective lens (scanning lens),

Total Magnification = 40x

B) With the 10X objective lens,

Total Magnification =100x

C) With the 40X objective lens,

Total Magnification = 400x

D) With the 100X objective lens,

Total Magnification = 1000x


1. What would you use to measure 42 mL of DI water?

We will use beaker to measure 42 mL of DI water.


2. What would you use to measure 1 mL of DI water?

We will use graduated cylinder to measure 1 mL of DI water.


3. What piece of glassware is best for making a hot water bath?

We will use beakers for hot water bath.


4. What is the difference between DI water and tap water?

 Distilled water from which impurities such as  salts and otherl particles have been removed by distillation. It is also called chemically pure water.

Tap water is water obtained directly from a faucet or tap, that has not been purified, distilled, or otherwise treated.


5. Name on major difference between a hot plate and a Bunsen burner.

Hot plates are simple electrical appliances used to heat samples within the air. Hot plates are generally used when the desired temperature is above 100 degrees Celsius (212 degrees Fahrenheit) and are regarded to be much safer than open-flame heaters such as Bunsen burners.

A Bunsen burner is a device that uses gas to produce an open flame used for heating or sterilizing equipment. The Bunsen burner can be adjusted to produce flames of different intensities.


6. When you observe the letter “e” slide under a compound light microscope and move the slide to the right, which direction does the “e” appear to move while looking through the oculars?

When I move the slide to the right while observing the letter ‘’e’’ slide under a compound light microscope, the ‘’e’’ will appear to move to the left.


7. When you observe the letter “e” slide under a compound light microscope and move the slide away from you, which direction does the “e” appear to move while looking through the oculars?

When observing the letter ‘’e’’ slide under a compound light microscope the ‘’e’’ will appear to move towards me while I move the slide away from myself while looking through the oculars.


8. Why is it important that the image is centered in the field of view before changing to a higher power objective?

We will have the object in the centre before we change objectives to increase the magnification, because the field of view becomes smaller, if the object is off to the side, it may disappear when you go to higher magnification. As it brightens, the light becomes less red and whiter. Closing the aperture through which the light passes increases the resolution of detail that you can see; use the iris diaphragm, which is operated by a lever among the condenser lenses, to change the size of the aperture. The higher the power of the objective lens, the less will be the depth of field.


9. What adjustment knob should never be used when the high power objectives are in place?

We should never use the coarse focus knob to focus downward with the high power objective or oil immersion objective in place. 


10. What objective lens is used when placing and removing slides from the stage? (HINT: what objective lens do you always start with?)

We will always start with 4x or 10x objective lens when focusing on a slide, we always start with 4x or 10x objective lens.


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