11
Through your microscope you should have noticed that tissues and
paper towel have soft, fuzzy fibers that have big air spaces between
them. These air spaces can also hold water, which is why these two
samples did well picking up the water spill. The writing paper did not
have these air spaces and did not pick up water very well. The newsprint
did not work well either because its fibers are also closely packed.
Project #6: Crystals
You will need: Your microscope
two clean, blank slides
string
a
drinking
glass
very warm water (enough to almost fill the glass)
a spoon (to measure and stir with)
table salt
sugar
Take a piece of string about 3 inches (7.6cm) long and tie it around the
center of an old pencil. Now take a small drinking glass and almost fill it
with hot water from the tap. Be careful not to burn yourself. Stir in a
spoonful of salt until it is well mixed and has all dissolved. Now stir in
another spoonful and stir it well. If all of the salt dissolves in the water, try
and mix in a third spoonful.
Now place the pencil across the top of the glass so that the string is
hanging in the salt water. Place the glass somewhere safe where small
children cannot reach it. Do not move the glass around. Just let it sit
quietly. Leave it for a day and then examine the string. Leave it another
day and examine the string once more.
You will see small white cubes growing on the string. These are salt
crystals. This crystal structure is salt’s basic shape.
Try the same experiment with a strong solution of sugar. Sugar also has
a crystal shape. Is it the same as a salt crystal? Can you tell them apart?
Look at some of the crystals you have grown under your microscope.
Sometimes the little cubes will join together in strange or beautiful
shapes.
12
Project #7: Insects
You will need: Your microscope
two clean, blank slides
tweezers
specimen
vials
Study the parts of ants, mosquitoes, spiders and flies. Handle the insects
with your tweezers and keep them in your specimen vials. Some can
look scary under a microscope. Can you see the powerful mouth parts
on some insects? They use these to eat plant parts or other insects.
Many insects have small hairs on their legs and bodies. These hairs help
plants. As the insect crawls from one plant to another small grains of
pollen get carried along. This pollen is needed by plants to reproduce. So
the insects are doing a good deed by spreading the pollen to many
plants.
Note the coloring on some insects. Insects with bright colors are flashing
a warning that says “Don’t eat me because either I am poisonous or I
don’t taste good. Don’t touch brightly colored insects, particularly
caterpillars. Wash your hands carefully when you are done.
Project #8: Pond Water
You will need: Your microscope
a pail or bucket
an
empty
jar
a
pipette
clean,
blank
slides
glass
slide
covers
Get a sample of water from a pond in a wooded area. It is best to get a
sample in the late Spring or Summer. Dip your pail or bucket in the pond
to fill it. Let it stand still for about a half hour. Then dip your jar to the
bottom of the pail and try and get some of the sludge that has settled to
the bottom. Use your pipette to place a drop on a blank slide and place a
slide cover over it. To do this, stand the slide cover on end next to the
drop. Gently let it fall onto the drop. Push it lightly with a toothpick, but
not hard enough to squash any little animals. If water has squeezed out
around the edges you can touch a paper tissue to it to clean it up. Look
through your microscope. Start at 80X.
What are all of the small things you see? Are some of them alive?
