Question 11
Materials: Eye protection such as safety goggles, dropper, water, glass slide, sterile cotton bud, methylene blue solution, coverslip, mounted needle, filter paper, microscope.
Procedure and Observations
1. Use a dropper to place a drop of water on a glass slide.
2. Use a sterile cotton bud to gently scrape some cells from the inside of your cheek.
3. Rub the end of the cotton bud with scrapings onto the centre of the glass slide.
4. Add a drop of methylene blue solution to the scrapings on the slide. This will stain some parts of the cell, making them easier to see.
5. Carefully lower a coverslip onto the slide as described in Activity 3B.
6. Place the filter paper at the edge of the coverslip to carefully soak up any excess liquid.
7. Place the slide on the stage of a microscope. Secure it with the stage clips.
8. Observe the cells using the steps described in Activity 3B. Use the low-power objective lens and then the high-power objective lens, focusing the image each time.
Caution: Use your own cheek cells and handle your own glass slide only. Place the cotton bud in disinfectant right after use. Do not allow the cotton bud to touch the bench. Handle the glass slide and coverslip with care as they can break easily. Methylene blue is harmful to skin and is dangerous to the eyes. It is also harmful if swallowed. Wear eye protection such as safety goggles. Do not touch the solution or put it in/near your mouth. Use it very carefully. Handle mounted needles with extreme care and only leave them in a place where you and others can see them. When turning the adjustment wheel to focus the image, do it slowly. When using the higher-power objective lenses, only use the fine adjustment wheel and ensure that the objective lens does not hit the glass slide.
9. Draw two to three cheek cells. Label the cell parts that you can observe. Record the magnification of the microscope.
Procedure and Observations
1. Use a dropper to place a drop of water on a glass slide.
2. Use a sterile cotton bud to gently scrape some cells from the inside of your cheek.
3. Rub the end of the cotton bud with scrapings onto the centre of the glass slide.
4. Add a drop of methylene blue solution to the scrapings on the slide. This will stain some parts of the cell, making them easier to see.
5. Carefully lower a coverslip onto the slide as described in Activity 3B.
6. Place the filter paper at the edge of the coverslip to carefully soak up any excess liquid.
7. Place the slide on the stage of a microscope. Secure it with the stage clips.
8. Observe the cells using the steps described in Activity 3B. Use the low-power objective lens and then the high-power objective lens, focusing the image each time.
Caution: Use your own cheek cells and handle your own glass slide only. Place the cotton bud in disinfectant right after use. Do not allow the cotton bud to touch the bench. Handle the glass slide and coverslip with care as they can break easily. Methylene blue is harmful to skin and is dangerous to the eyes. It is also harmful if swallowed. Wear eye protection such as safety goggles. Do not touch the solution or put it in/near your mouth. Use it very carefully. Handle mounted needles with extreme care and only leave them in a place where you and others can see them. When turning the adjustment wheel to focus the image, do it slowly. When using the higher-power objective lenses, only use the fine adjustment wheel and ensure that the objective lens does not hit the glass slide.
9. Draw two to three cheek cells. Label the cell parts that you can observe. Record the magnification of the microscope.
