CHAPTER 14 Ten Basic Experiments 89
You need:
✔✔A glass jar or similar
✔✔A Petri dish or glass slide with coverslip
✔✔A dropper
Take your glass jars and make a little excursion to the next pond or
puddle to collect some water with some mud and wrotten leaves. If
there are no ponds nearby, water from the banks of a lake, river or
stream will suffice. You need to settle the dirt to the bottom before
you use the dropper to take a sample. Drop some liquid into your
petri dish or on the glass slide. By the way – if you have a concave
slide it’s much easier to hold the water in place. Carefully place
the
coverslip on the slide to avoid harming any organisms. Have a look
with your microscope using the lowest magnification first. Do you
see anything? Be patient, as some creatures may take a while to calm
down and hold still. You will find a lot of planktonic microorgan-
isms including:
✔✔Bacteria
✔✔Algae
✔✔Protozoa (which are mostly larger than bacteria)
✔✔Small animals like arthropods
✔✔Hydras (small animals with tentacles)
Yeast Cells
Yeasts are fungi that are used to make bread, beer and wine by fermentation.
Bread yeast is a nice sample to study cellular processes. The yeast uses sugars in
the flour or from cereals, producing alcohol ethanol and bubbles of the gas carbon
dioxide. In case of bread the gas makes the dough rise.
You need:
✔✔A glass jar or bowl
✔✔Warm water
✔✔Active yeast