Bio111 lab microscope PDF

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lab on how to use a microscope
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Introduction to the Microscope

PRE-LAB QUESTIONS 1. Label the following microscope using the components described within the Introduction.

Ocular lens

head

Revolving nose piece Objective lens

Course focusing

clips Fine focusing stage

diaphragm

arm

Light source

base

Introduction to the Microscope

Introduction to the Microscope

EXPERIMENT 1: VIRTUAL MICROSCOPE Purpose (What question is this experiment designed to answer?): *Does using a compound microscope help us see things that the naked eye cannot see while looking at a newspaper clipping of the letter “E”? Hypothesis (Based on what you’ve learned in the pre-lab materials, write and If/Then statement regarding the outcome of this experiment.): *If I put a letter E’” under the compound microscope and use different magnifications, then I will see things I didn’t see with a naked eye.

Claim (What are the results of your experiment?): *Placing the newspaper clipping of the letter “E” on a slide and placing it under the microscope at different magnifications, 4X, 10X, and 60X, I increased the amount of detail I saw

with each advance in magnification. As I went higher in magnification, I was able to see less of a sold black “E” and more of the paper fibers through the ink.

Evidence (What data did you collect that supports your claim? Explain the meaning behind the data and the calculations.): My data are pictures of how the “E” looked at different magnifications. The 4X magnification allowed me to see most of the surface on the letter “E” and paper, and as I moved on to the 10X, I was able to see lines and fibers on the paper the ink bleeding through the fibers. When I used the last magnification 40X, I saw less black ink and more paper fibers.

Post-Lab Questions Virtual Microscope 1. What is the first step normally taken when you look through the ocular lenses?

 When looking through the ocular lens, your first step is to adjust the eyepiece to line up with the light. If you have a binocular microscope, you need to line up both eyes so you only see one circle of light. (“Stanford Virtual Lab)”

2. What does it mean that the image is inverted when you look through the ocular lenses?

Introduction to the Microscope It means that the image you see through the eyepieces is inverted and backwards relative to how that object is oriented on the slide. This is due to the mirrors that direct the light coming off the image to your eyes ("Stanford Virtual Lab")

3. What is the difference between the coarse adjustment knob and the fine adjustment knob? When is it appropriate to use them?

*The coarse adjustment knob is used to get the specimen into focus. Most of the time coarse adjustment knob is enough to get the 4X and 10X magnification into view but you can use the fine focus knob to get a sharper image. (“Stanford Virtual Lab”). The coarse focus knob is

always the bigger of the two knobs. You should only need to use the coarse focus knob at the beginning on each slide. Start it with the lowest power to get the specimen into focus. (n.d.) The fine adjustment knob is the smaller of the two knobs. This is the focus knob that you will use the most. (n.d.) You want to make sure when using the fine focus knob, it is to towards the middle of its range to check if there is some “play” before getting started. (“Stanford Virtual Lab”).

4. What new details are you able to see on the slide when the magnification is increased to 10x that you could not see at 4x? What about 40x?

With each new magnification you use, you are able to see a different surface of the specimen. As the magnification increases, the depth of field decreases. Low magnification 4X, for example you might be able to see the entire volume of the specimen. But every time you increase the magnification to 10X or 40X you lose the entire volume and now see one layer of the specimen. Also the higher the magnification you go the closer to the object lens is to the specimen. Working distance is inversely proportional to magnification. (Ellen Murphy, 2018)

Reflection (Discuss what you have learned by doing this experiment. How have your ideas changed? Do you have any new questions? What connections did you make between the lab and lecture?): During this experiment I relearned how to use a microscope. It has been over 15 years since I used a microscope, so it was an outstanding assignment. A question that I thought of during the experiment was if my eyes have gotten worse since my last eye exam. Every time I tried to focus the low mag and high mag of the microscope tutorial I couldn’t get it to move on to the next step even though it looked clear to me. I had my husband see if he could do it. An experiment must be able to be retested. When he tried the Stanford virtual lab, he couldget the magnification just right to move on the next step. and I thought it looked blurry when he did. My ideas have changed drastically since the last time I took a biology class. For one, when I was nineteen I just tried to get through the assignment and I didn’t learn anything. Now, I enjoyed learning how it all works. I cannot wait to dive into what things look like under the microscope. I made several connections between the lab and the lecture. I went back to chapter one of the textbook and used the scientific method to form the prelab questions. I asked myself, questions

Introduction to the Microscope about how I would use the microscope to come up with a purpose and a hypothesis to explain how I would use the microscope test the letter “E”. I also asked myself what magnification I would use to see different layers of the specimen. (Mary Ann Clark Texas Wesleyan University

et al., 2018, pp. 10-16)

Hands-On Microscope 1. What observations do you make observing the letter “e” at low power?

a. The observations that I made while looking at the “E” on the lowest power were that I could not see the entire letter “E” but, you could see the dark black line. However, the line was not solid like you see without the microscope you see breaks in the black lines because, the fibers of the paper are magnified. You can also see the fibers of the newspaper throughout the entire slide that was

2. At what objective magnification can you no longer see the entire letter when looking through the ocular lens? On the lowest power 15xby4x (60) I could not see the entire “E” at the lowest magnification 4X. However, I could see most of the letter and the “E” was still black with some of the white fibers of the paper showing through that black letter “E”

3. List the objective lens magnifications you used to observe the letter “e” below, along with your observations at each magnification.

4x: I could see most of the letter “E” but it did not look as black as it does with just my eye. I could see more of the fibers of the paper.

Introduction to the Microscope

10X: I noticed that you see less white of the newspaper and more black but not true solid black lines. It still has breaks in the black. The fibers are more pronounced at this magnification.

40X: I observed that the “E” is no longer a dark line and more thin black lines that remind me of what a leaf would look like. Since I didn’t see a full black “E” like you do with your naked eye you see actually more white than you so black and the black that you do see are very fine lines. I can see fibers of the paper.

4. What did you use to create your second microscope slide?.

Introduction to the Microscope a. I used a leaf from a tree in my backyard.

5. Write down your observations in viewing you second slide, and write down what magnifications you used to make those observations.

4X

10X

4X: I observed a dark green area of the leaf and a lighter green area which are the veins in the leaf. You could see how pronounced the veins are in the leaf are. 10X I observed, that you can still see the light and dark green color of the leaf but now you are able to see very small bumps on the darker part of the leaf. Also the veins in the leaf are in more magnification. 40X: I could not get enough light through to be able to see any detail at the 40X magnification. I should have chosen something that had more transparency or a single layer at that magnification.

Reflection (Discuss what you have learned by doing this experiment. How have your ideas changed? Do you have any new questions? What connections did you make between the lab and lecture?): I learned how much more detail is in things that you cannot see without magnification. I think most people especially myself overlook what something is truly made up of and how all these small details matter to make the object we see with our naked eye. I don’t really have a question more a statement. I find it hard to think left is right and right it left, etc when trying to move the slide to get it into view. That will take some getting used to. The connections I made from the lab to lecture is that without the lecture on how to use a microscope I would not have been able to focus as well as I did on the letter “E” and the leaf. The connection I made of the leaf to lecture when I was looking at the leaf was how it’s a eukaryotic cell, and how photo synthesis works inside the leaf. While examining the leaf I thought of what type of organisms were in the leaf compared to me. Chloroplast the helps with photosynthesis and the cell wall that helps with protection, structural support, and maintenance of the cell. (Mary Ann Clark Texas Wesleyan University et al., 2018, pp. 101-118).

Introduction to the Microscope

Ellen Murphy, E. L. (2018, April 17). What Happens When You Go From Low Power to High Power on a Microscope?Https://Sciencing.Com/Happens-Power-High-PowerMicroscope-8313319.Html. https://sciencing.com/happens-power-high-powermicroscope-8313319.html

Mary Ann Clark Texas Wesleyan University, Jung Choi Georgia Polytechnic University, & Matthew Douglas Grand Rapids Community College. (2018). Biology 2e by OpenStax (hardcover version, full color) (2nd ed.). XanEdu Publishing Inc. Sandford Virtual Lab W. (n.d.). The Parts of a Compound Microscope and How To Handle Them Correctly | Human Anatomy and Physiology Lab (BSB 141). Https://Courses.Lumenlearning.Com/Ap1x94x1/Chapter/the-Parts-of-a-CompoundMicroscope-and-How-to-Handle-Them-Correctly/. https://courses.lumenlearning.com/ap1x94x1/chapter/the-parts-of-a-compoundmicroscope-and-how-to-handle-them-correctly/...