Experiments .....

Water / Science Fun

Activities for Kids:
There are a variety of experiments that can be done at your home or even in the backyard. Listed below are just a few experiments you might like to try.

The Cow's Moo: An Activity with Milk

Milk is something most of us drink everyday, but it has unique characteristics that many people are not aware of. Milk is a complex substance made up of many parts. This experiment will demonstrate that there is more to milk than meets the eye.

What You Will Need (per student or group):
· ¼ cup whole milk
· 1 teaspoon liquid dishwashing detergent
· 2 wooden toothpicks
· 1 milk carton, aluminum pie plate, or plastic Petri dish
· 4 different kinds of food coloring
· Safety scissors
· Tablespoon measure
· Optional for Step 6- ¼ cup each of skim milk, half-and-half, and cream

Before You Begin:
Have you every wondered what milk would look like under a microscope? Or
have you ever wondered what the words "HOMOGENIZED" and
"UNHOMOGINIZED" mean on the carton of milk you use for your cereal in the
morning? If so, this experiment will teach you not only what these terms mean
but also a variety of other amazing concepts about milk.

What You Get To Do:

STEP 1: With the assistance of your adult leader, cut off the top half of a
student milk carton or use another container. Pour whole milk into
the container, to a depth of about 1 cm.

STEP 2: Place a drop of each of 4 different food colors in the milk (one drop in
each corner) in the dish.

STEP 3: Dip a toothpick into liquid dishwashing detergent. Then touch the
toothpick into the middle of the dish. Record what happens in your lab
notebook.

STEP 4: Try again with more detergent, touching the milk in different areas.
Record what happens in your lab notebook.

STEP 5: Think about what you saw? Can you explain why the milk did that?

STEP 6: (Optional) Repeat the activity by using the same steps with different
kinds of milk. Try using ¼ cup of skim milk, then try ¼ cup of half
and-half or cream. Record what you saw and how the milk changes.

WHAT IS GOING ON HERE?

The milk you are working with has a more complicated nature than is apparent. It
is made up mostly of water and then equal parts of protein, fats, and sugars. The
fat has been broken up and spread throughout the milk, by the process of
homogenization, into tiny spheres of fat called globules.

When the milk was first placed into the carton, it was still and we saw no motion.
Even with the food coloring added to the milk, things were still quiet. This is
because the fat globules were steady and undisturbed. When the soap hits the
milk, things begin to change.

The soap breaks up these fat globules and allows then to spread out across the
surface of the milk. As the tiny globule breaks and expands, it creates movement
in the otherwise still milk. Normally you would never notice this, but the food
coloring shows how the "skin" of the milk moves and changes in response to the
soap breaking up the fat globules.

This flowing is pretty and interesting, but more importantly it shows how soap
works. It is the same kind of thing that happens when you wash dishes or hair
with soap. The soap breaks up the fat or grease and allows it to flow in the water
and down the drain.

* * This activity is from the American Chemical Society.
For more information on additional chemical experiments, please call 800-ACS-5558. * *