Brooke Forseth

Biology 1

Microscope Lab Project

eyepiece

Objective lenses

1000x objective

Mechanical stageIris

diaphragm

illuminator

arm

Stage controls

fine focus

6. Describe the relationship between what you see through the eyepiece and what you see on the stage.Answer: The relationship between what I see through the eyepiece and what I see on the stage is that on the stage it is backwards, the e is in a different position when you look in the eyepiece than it actually is.7. Looking through the eyepiece, move the slide to the upper right area of thestage. What direction does the image move? Answer: The image moves down right8. Now, move it to the lower left side of the stage. What direction does the image move? Answer: The picture moves to the right and down9. Re-center the slide and change the scope to high power. You will notice the "e" is out focus. Do Not touch the coarse focus knob, instead use the fine focus to resolve the picture. Draw the image you see of the letter e (or part of

it)

100x

on high power. Label!

10. Locate the diaphragm under the stage. Move it and record the changes in light intensity as you do so.Answer: As the light intensity changes I noticed that the light is more intense the farther away from the image you get.

_______________________________

III. Plant & Animal Cells Close Up!1.Using the wet-mount technique described above to prepare slides of various plant

or algae specimens available in the class and sketch your observations in your lab report.

2. Using a clean toothpick, gently scrape the inside of your cheek. Swirl the “cheek” end of the toothpick in a drop of water on a glass slide. Add a drop of Iodine to the mixture and complete making a wet mount. View under low, medium and high power and sketch your observations in your lab report

2.Examine under various powers at least three of the prepared slides provided. Sketch in detail and label where you can.Answer: sketches can be found under pond scum lab as well

Cell membrane

4. Take several samples of “pond scum” provided and search for organisms. Once you locate one that stays put long enough to sketch, do so! Good luck! Be sure to note any behaviors of your organism – think like a scientist!

Pond Scum lab

IV. Determining Total Magnification:Locate the numbers on the eyepiece and the low power objective and fill in the blanks below.Do the same for the high power objective.Eyepiece magnification 10x

nucleus

Cell membrane

cytoplasm

(X)Objective magnification 40=Total Magnification 400XEyepiece magnification 10(X)Objective magnification 100=Total Magnification 1000X3. ___________________________________________________Write out the rule for determining total magnification of a compound microscope.Magnification of eyepiece times the magnification of the objective lens

Conclusion Questions:1. State 2 procedures which should be used to properly handle a light microscope.-hold microscope with both hands-wait for direction before proceding to use microscope after it is turned on2. Explain why the light microscope is also called the compound microscope.Answer: Because it is made up of more than one lens3. Images observed under the light microscope are reversed and inverted.

Explain: the different lenses reverse and invert the image making it appear upside down or right-side up, a light microscope uses lens and light to zoom in on the visual.4. Explain why the specimen must be centered in the field of view on low power before going to high power.Answer: The specimen must be centered in the field of view on low power first because you have to back up and look at the slide and go from there, choosing the point of the slide you want to zoom in on. After you find the most concentrated spot in the slide you slowly go to a higher power.

5. A microscope has a 20 X ocular (eyepiece) and two objectives of 10 X and 43 X respectively:a.)43X20=860b.)10X20=200

6. In three steps using complete sentences, describe how to make a proper wet mount of the letter e. Describe the changes in the field of view and the amount of available light when going from low to high power using the compound microscope.Answer: In order to make a proper wet mount of the letter e first you must cut out a picture of a small cased e in a newspaper, after this you place it on the glass slide and add 1 or 2 drops of water, you then put on the top glass slide and slowly press on it to remove all necessary air bubbles and until it sticks. It does not have to be perfect After you have prepared your slide you bring it to your microscope and place it on the stage. First observe it on a low power looking for the whole picture of the “E”. Then you can slowly zoom in on the e to reveal the creaks and crevices of the e. The amount of available light from low to high power is that under a low power the light is not as strong as it is under a high power.

7. Describe the changes in field of view and the amount of available light when going from high power to low power using the compound microscopeAnswer: the higher the power the less the less available light, the lower the power the more available light. The field’s depth decreases when the lens is on high power and increases when the field is on low power.

8. Explain what the microscope user may have to do to combat the problems incurred in question # 7.Answer: Use the microscope in a lighter area and don’t zoom in too close or you wont be able to see the picture

10. Indicate and describe a major way the stereomicroscope differs from the compound light microscope in terms of its use.Answer: stereomicroscopes have a lower range but a large field of view and a way better ability to perceive depth than the light microscope

9. How does the procedure for using the microscope differ under high power as opposed to low power?Answer: under high power you can see into the cells and crevises, whereas under low power you see the power more blurred and less detailed.Indicate and describe a major way the stereomicroscope differs from the compound light microscope in terms of its use.

11. What is an electron microscope? What are the various applications for science for such a tool?Answer: An electron microscope is a microscope type that produces an electronically-magnified image of a living or non-living organisism for detailed observation.

12.) Microscope History Timeline

R

------14th century-----------------------1590----------------1667---------------------1903-----

\

---------------1932--------------------1938---------------------------------------1981-----------

Robert hooke studies cork in relation to cells

Grinding lenses made to improve eyesight

Richard Zsigmondy discovers the ultra grinding lenses made to microscope

First microscope made by Hans and Zacharias Jenssen

Frits Zernike invents phase-contrast microscope

Ernst Ruska makes the electron microscope which improves resolution extremely

Gerd Binnig and Heinrich Rohrer invent scanning tunneling microscope