This activity will increase your familiarity with compound microscopes. Record all your responses in your journal.
•compound microscope, •medicine dropper, •beaker of water, •slide, •coverslip, •newspaper, •scissors.
- Using the proper technique, carry your microscope to your assigned workstation.
- Open the diaphragm to the largest hole.
- Make a wet mount slide using the letter 'e' from a newspaper.
- Cut out a lower case 'e' from a newspaper.
- Place the letter on a clean slide as if you were going to read it.
- Cover the letter with a drop of water.
- Place one edge of the cover slip on slide next to the letter 'e' and let the coverslip drop onto the letter.
- Using proper technique focus the letter.
- Record: What part of the microscope moves when you turn the coarse adjustment?
- While looking at the letter under low power answer the following:
- Record: When you move the slide to the right, what happens to the image in the microscope?
- Record: When you move the slide toward you, what happens to the image in the microscope?
- While looking at the letter using the microscope, change the diaphragm setting.
- Record: What is the purpose of the diaphragm?
- While watching from the side, carefully move the objective from the low power to the high power. If you have made your slide properly the objective will NOT hit the coverslip.
- Record: Is the field of view (FOV) larger or smaller when using high power?
- Record: Is the field brighter or darker on high power?
- Record: Why do we use only the fine adjustment on high power?
- Record: Why must you center in the field of view and focus under scan before changing to low or high power?
- Record: What did the microscope do to the orientation of the letter 'e' image?
- Record: Why should a wet mount have no bubbles under the coverslip?
Record: Copy and complete this table in your journal. The FOV can be measured on scan and low using a transparent ruler. Remembering that the FOV decreases by the same factor the magnification increase, calculate the high FOV.
Record in journal Objective lens Ocular lens Total magnification FOV Scan