Question

pre - lab activity cont. scanning - when you are ready to look at an object with the microscope you should always start with the scanning objective. once you have found the object, position it in the middle of the field of view. use the coarse adjustment knob to sharpen the focus as much as possible. then, use the fine adjustment knob until you see all the detail. low and high power - switch to low power by rotating the objective into place. adjust the focus with the fine adjustment knob. caution: do not use coarse adjustment while using low or high - powered objectives because you could break or damage the lens. when you are ready to see the object under high power, rotate the objective into place and use the fine adjustment to bring the object into focus. care of your microscope - the lenses should be cleaned periodically, but make sure you only use lens paper to clean lenses. when you are finished with your microscope you should always turn the objective back to the scanning lens, carefully unplug and wrap up the electrical cord, and carry your microscope with one hand on the arm of the microscope and your other hand supporting the base of the microscope. pre - lab questions: 1. why do biologists use microscopes? 2. when do you use the coarse adjustment knob on a microscope? 3. what do you think you should do if you were looking at a focused organism using low power, but couldnt see the image when you switched to high power? 4. why should you always return your objective back to the scanning lens when you are finished? 5. when you draw an image that you see using a microscope, why is it important to write the magnification used next to the drawing?

Explanation:

1. Biologists use microscopes to view organisms and structures too small to be seen with the naked - eye, enabling detailed study of cells, tissues, and microorganisms.
2. The coarse adjustment knob is used when initially focusing on an object under low - power magnification to bring the object into general focus quickly.
3. If you can't see the image when switching to high power after focusing on low power, first check if the object is centered in the field of view on low power. Then, use the fine adjustment knob to refocus as high - power lenses have a shallower depth of field.
4. Returning the objective to the scanning lens when finished protects the lenses and the microscope. The scanning lens has the shortest focal length and is less likely to be damaged or to damage the specimen.
5. Writing the magnification next to a microscope - drawn image is important because it provides context for the size of the object being depicted. Others can then understand the relative size of the structures shown.

Answer:

1. To view organisms and structures too small to be seen with the naked eye for detailed study.
2. When initially focusing on an object under low - power magnification to bring it into general focus quickly.
3. Check if the object was centered on low power and use the fine adjustment knob to refocus.
4. To protect the lenses and the microscope as the scanning lens is less likely to be damaged.
5. To provide context for the size of the object being depicted so others can understand relative size.