- Compound light microscope
- Microscope slides
- Slide cover slips
- Methylene blue stain, 1% aqueous
- Clear adhesive tape
- Chemical-resistant gloves
- Safety goggles
Methylene blue is a vital stain—it stains nearly everything, including skin and clothing. Prevention is the key when working with vital stains. Wear chemical-resistant gloves and avoid contact with eyes and skin. Wear safety glasses or chemical splash goggles whenever working with chemicals, heat, or glassware in the lab.
- Wash the underside of your wrist with soap and water.
- Take an inch or so of clear adhesive tape and press it onto the back of your hand with your fingertip (to avoid getting a finger print on the tape).
- Pull the tape off your hand and mount it on the microscope slide, sticky side down. Tweezers are useful for doing this to avoid getting your fingerprint on the tape.
- Put on a pair of chemical-resistant gloves.
- Lift one corner of the sticky tape and place one drop of methylene blue onto the microscope slide and just under the tape. The liquid will move across the slide under the tape.
- Make sure the lowest power lens (the shortest lens) is in place over the stage. Place the slide onto the stage of the microscope.
- Look through the eyepiece and turn the coarse focus knob (the largest knob) until an image comes into focus. It should look like scattered blobs. Move the slide around until a nice cluster of blobs moves into the center of your image.
- Use the fine focus knob (the smallest knob) to make the image as focused as possible.
- Observe the slide using the 10x objective. Can you see any cells?
- Draw one of the cells that you see and label the cell membrane, cytoplasm, and nucleus.
What did you notice about your skin cells before you used the methylene blue?
How did the methylene blue help you see your skin cells more clearly?
What parts of the cell can you see through the microscope and at what magnification do you see them?
Compare this slide of skin cells to the slides of the human organ cells you saw earlier. Do they look the same? Do all of the cells from the various organs look the same? Why or why not?
Do you see the same structures among all of the various organ cells?
Do you see different structures between the different organ cells?