Science 8 Observing Onion Cells
***Do not write anywhere on this piece of paper!!! It will be used again this afternoon!!!*****
Instructions. On a piece of paper, write the title (see above), the date, your block, and your name.
Then copy out the problem (see below).
Problem. What structures can you observe in an onion cell when using a compound light microscope?
Hypothesis. On your lab report, below your Problem, write a Hypothesis that will “answer” the problem. Start your hypothesis with, “If onion cells are observed under a microscope, then….” Have Ms. Jonzon approve your Hypothesis before moving on.
Materials. You do not need to copy out this list of Materials (or the Procedure …show more content…
1. Have one partner take a microscope from the back of the room. Remember to carry it with one hand on the arm and one hand on the base. Find an outlet to plug in your microscope. Then this same partner can pick up the eye dropper.
2. The other partner should pick up a slide, cover slip, onion, paper towel, and tweezers from the front counter. Pick up the slide and the cover slip by the edges to avoid fingerprints as well.
3. Now you are going to make a wet mount. Use your tweezers to peel off a small thin section of onion from the concave side of the onion. Place this thin section on your slide. Remember to hold the slide by the edges!
4. Put 2-3 drops of water onto the onion on the slide.
5. Use the tweezers or your fingers to gently pick up the cover slip. Line up the edge of the cover slip with the edge of the onion on your slide. Place the cover slip at a 45° angle to the slide, and then slowly lower it over the onion (see Figure 1 below).
Figure 1. Making a wet mount slide.
6. Carefully press down on the cover slip with the tweezers to remove as many bubbles as possible. You are now finished making your wet mount