Day 1/21: Monday Biology Week #21 Week of: January 21st-25th Root Words In-Class Homework Word: Definition: As in: - Picture: NO SCHOOL: MLK Day 1/22: Tuesday Word: Definition: As in: - Picture: -Microscope Notes -Lesson on Focusing the Microscope 1/23: Wednesday Word: Definition: As in: - Picture: -Microscope Practice Prepared Slide and Wet Mount Slide 1/24: Thursday Word: Definition: As in: - Picture: - Microscope Practice Prepared Slide and Wet Mount Slide 1/25: Friday Word: Definition: As in: - Picture: -Week #21 Quiz -Microscope Lab Practical Quiz Need Help? Raymond Houk Lundgren Lesniak McKittrick McCormack Monday 127-7th 205-7th Tuesday 298-8th 194-4th 245-7th T.C. - Pd. 1 Wednesday 127-7th 205-7th Thursday 298-8th 194-4th 245-7th T.C. - Pd. 1 Friday 127-7th 205-7th AM = before school, PM = after school, T.C. = tutoring center Or you can always make an appointment Website = GOOGLE CLASSROOM ( About tab) Annotation Guidelines: Red (vocab), Orange (questions), Blue/Black (notes or answers to analysis questions) 1
Microscope Notes Problem: What is the purpose of using a microscope? What is a compound light microscope? What is a stereoscope? What is a scanning electron and transmission electron microscope? 2
PART FUNCTION Arm Carry the scope with arm in one hand Base Carry the scope with base in other hand Eyepiece (Ocular lens) (10X) To look at specimen (10X magnification) Revolving nosepiece Turn to get desired objective lens Scanning Power Objective (4X) Starting position, magnifies object 40X Low Power Objective (10X) Magnifies object 100X High Power Objective (43X) Magnifies object 430X Stage clips Holds slide in place Stage Where specimen/slide is placed Stage opening Allows light through the stage Diaphragm Permits sufficient light to enter scope Lamp Light source Coarse adjustment knob Moves objective lens closer to specimen for focusing when you are on scanning/low power only!!! Fine adjustment knob Moves the objective lens closer or away from specimen for focusing. Use when you have specimen in view to get fine, clear focus How much does a microscope magnify? Objective Low Power (green) Magnification of Eyepiece Magnification of Objective Total Magnification High Power (yellow) What are the steps to prepare the microscope? What are the steps to focus a microscope in low power? Describe how microscopes change an image. 3
What are the steps to focus the microscope in high power? Describe the difference in the image in low power vs. high power. Describe a prepared slide. What are the steps to make a wet mount slide? What are the steps to clean up a microscope? Problem: What is the purpose of using a microscope? 4
Introduction to the Light Microscope Introduction: Read and annotate the following paragraphs and answer the questions. Many objects are too small to be seen by the eye alone. They can be seen, however, with the use of an instrument that magnifies, or visually enlarges, the object. One such instrument, which is of great importance to biologists and other scientists, is the compound light microscope. A compound light microscope consists of a light source or mirror that illuminates the object to be observed, an objective lens that magnifies the image of the object, and an eyepiece (ocular lens) that further magnifies the image of the object and projects it into the viewer s eye. Objects, or specimens, to be observed under a microscope are generally prepared in one of two ways. Prepared slides are made to last a long time. They are usually purchased from biological supply houses. Wet mount slides are made to last only a short time usually one laboratory period. The microscope is an expensive precision instrument that requires special care and handling. In this investigation, you will learn the parts of a compound light microscope, the functions of those parts, and the proper use and care of the microscope. You will also learn the technique of preparing wet-mount slides. It is important to hold the microscope by both the arm and base. Refer to Figure 1. Please write in complete sentences!!! 1. Why do scientists use microscopes? 2. What is a compound light microscope? 3. What are the 2 ways specimens are prepared? 4. How do you hold and carry a microscope? 5
Microscope Parts : Complete the diagram below using the words in the word bank. Word Bank: Arm Diaphragm Low Power Objective Base Eyepiece (Ocular Lens) High Power Objective Coarse Adjustment Knob Fine Adjustment Knob Revolving Nosepiece 1. The magnification on the ocular lens (eyepiece) is. 2. The magnification on the low power objective is, while the magnification on the high power objective is. 3. The total magnification using the lenses can be determined by multiplying the objective lens with the ocular lens. Complete the table below for the different magnifications. Objective Magnification of Eyepiece Magnification of Objective Total Magnification Low Power High Power 6
Using a Compound Light Microscope Lab Part A: Prepared Slide 1. Set up the microscope following the directions in your notes (use page 7 for help). 2. Focus on a prepared slide using low power (use page 7 for help). 3. Show your teacher your microscope s field of view when focused in low power. a. Teacher Check: 4. Draw what you saw under low power in the first circle below. 5. Now, focus the microscope in high power (use page 8 for help). 6. Show your teacher your microscope s field of view when focused in high power. a. Teacher Check: 7. Draw what you saw under high power in the second circle below. 7
Part B: Wet Mount Slide The Letter e 1. Set up the microscope following the directions in your notes (use page 7 for help). 2. Prepare a wet mount slide using a cut out of the letter e (use page 8 for help and Figure 4). 3. MAKE SURE THE e IS FACING YOU WHEN YOU PUT IT ON THE STAGE!!! 4. Focus on the wet mount slide using low power (use page 7 for help). 5. Show your teacher your microscope s field of view when focused in low power. a. Teacher Check: 6. Draw what you saw under low power in the first circle below. 7. Now, focus the microscope in high power (use page 8 for help). 8. Show your teacher your microscope s field of view when focused in high power. b. Teacher Check: 9. Draw what you saw under high power in the second circle below. 8
Part C: Prepared Slide Crossed Threads 1. Set up the microscope following the directions in your notes (use page 7 for help). 2. Focus on a prepared slide using low power (use page 7 for help). 3. Show your teacher your microscope s field of view when focused in low power. a. Teacher Check: 4. Now, slowly turn the fine adjustment knob while looking at the threads at the same time. Can you focus all 3 threads at the same time? Why or why not? (Discuss with your teacher if you do not know). 5. Draw what you saw under low power in the first circle below. 9
Part D: Stereoscope At the last station you will find a stereoscope or a dissecting microscope. Look at the object under the stereoscope and answer the following questions. 1. Describe in one COMPLETE sentence what you see when looking through the stereoscope. 2. Describe two differences between the stereoscope and the compound light microscope. a. b. 10
Part E: Analysis and Conclusions : Answer the questions below in COMPLETE SENTENCES. 1. How is the image of an object seen through the high-power magnification different from the image seen through the low-power magnification? 2. How does the letter e as seen through the microscope differ from the way an e normally appears? 3. What is the difference between a prepared slide and a wet mount slide? 4. What level objective (high or low) do you start your viewing? Why? 5. Why might it be a good idea to keep your microscope at least 10 cm from the edge of the table? Part F: True or False - Answer true or false to each of the following statements. 1. On high power, you should use the coarse adjustment knob. 2. The diaphragm determines how much light shines on the specimen. 3. Stereoscopes magnify more than compound light microscopes. 4. Images viewed in the microscope will appear upside down. 5. If a specimen is thick, only parts of the specimen may come into focus. 6. The type of microscope you are using is a scanning electron microscope. 7. In order to switch from low to high power, you must rotate the revolving nosepiece. 8. The total magnification of a microscope is determined by adding the ocular lens power to the objective lens power. 11