Activity #35 A License To Learn Part One: Earning a License Challenge Question: Initial Thoughts:

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1 Activity 35 Recording Sheets, p. 1 Activity #35 A License To Learn Part One: Earning a License Challenge Question: Initial Thoughts: Evidence: Objective Powers: Low = x Medium = x High = x Total Magnification= x The Microscope 5 Commandments Act # 35 pg 1 of 6

2 Activity 35 Recording Sheets, p. 2 How to prepare your microscope for Storage How to Focus: Focusing Steps 1-10 Step 1: Plug in the microscope and turn on the lamp. Make sure the low power objective is in position and turn the coarse focus knob until the stage is raised completely. Step 2: Set the diaphragm to its largest opening (where it allows the most light through). Step 3: Place the slide on the stage so the specimen is positioned right over the aperture. Wait to secure the slide with stage clips until after the slide is in focus. Step 4: While looking through the eyepiece, begin to slowly turn in the coarse focus knob. Turn slowly and watch carefully until the object is in focus. Secure the slide with stage clips. Step 5: When the specimen is focused under low power, move the slide so that what you want to see is dead-center in your field of view. Step 6: Without touching either of the focus knobs, switch to the medium power objective. DO NOT touch the coarse focus again you could break something! Step 7: Using the fine focus knob, focus the slide once again. If it doesn t work, start all over again and go back to STEP 1. Step 8: Once you are in focus using the medium power, move the slide so that what you want to see is dead-center in your field of view. Step 9: If you want to further magnify the slide, you may want to consider switching to high power. Without touching either of the focus knobs, switch to the high power objective while making sure it does not hit the slide. Step 10: To focus using a high power objective, use the fine focus knob ONLY. Be sure to center your specimen before switching to a higher power objective or it may disappear from your field of view. Act # 35 pg 2 of 6 129

3 Name Date Activity 35 Recording Sheets, p. 3 What Does Magnification Mean? 1. Examine your school microscope. What are the possible magnifications? Power Eyepiece Objective Total Magnification Low Medium High 2. Calculate the total magnifications for the following microscope lenses: Eyepiece Magnification Objective Magnification Total Magnification 10x 10x 5x 15x 4x 20x 12x 40x 3. Here is a small object. a. How much bigger do you think it would look under a microscope with a 2x eyepiece and a 3x objective? Write your prediction below. b. Draw the object as it would look c. Now draw what your drawing if magnified 2x. Use a ruler to in 3b would look like magnified double its diameter. 3x. Use a ruler to triple its diameter The Regents of the University of California d. Use your ruler to compare the length of your second drawing (3c) to the tiny object you were given at the beginning of this chapter. How many times bigger is the image? Science and Life Issues Student Sheet 35.2 C-83

4 Name Date Activity 35 Recording Sheets, p. 4 Problem-Solving Model 1 4. Here is another small object: Here is a magnified image of that object: a. What is the magnification? b. What was the strength of the objective lens used, if the eyepiece was 10x? 2006 The Regents of the University of California Science and Life Issues Student Sheet 35.3 C-85

5 Activity 35 Recording Sheets, p. 5 Part 2: Using the Microscope Name of Specimen: Power: Name of Specimen: Power: Analysis Questions (answer in complete sentences) 1. How does the microscope change the image you see? HINT: Compare the material you placed on the stage with what you see through the eyepiece. 2. Describe how the material(s) that you observed looked under low as compared to medium power. What differences did you observe? How did this compare to with what you saw with your eyes? 3. How do changes in magnification affect your field of view? Summary: After completing this activity, my improved or extended answer to the challenge question is. Specific evidence that supports my answer includes.. (Cite data and information from the actual activity and Evidence section) 130 Act # 35 pg 5 of 6

6 Activity 35 Recording Sheets, p. 6 Bubbles, Dust, or Micro-Life? Air Bubble Dust dust coverslip edge Micro-Life 2006 The Regents of the University of California microbe debris From a hay infusion at Lawrence Hall of Science. Your slide may look different. Science and Life Issues Transparency 35.1 C-87