|
Questions to Ask
Have the children ever had chocolate milk? What does it look like?
If you had strawberry milk, what color would it be? What about grape
milk?
Does the bowl of colored milk remind them of anything else?
Tips for Less Mess: Cover the work area with newspaper or old towels.
Paper towels and a garbage bag would be helpful.
Science Connection
Taken from Super Science Concoctions by Jill Frankel Hauser. A
Williamson Kids Can! Book. 1997.
“One end of a detergent molecule is attracted to water and
the other end is attracted to grease (fat). Milk contains both fat
and water, so when you add detergent those soap molecules start
grabbing onto their favorite parts of the milk. Food coloring is
made mostly of water so it mixes with the water part of milk. All
this molecular grabbing, moving, and mixing is what you see as explosions
of color.”
|
Why
To watch colors erupt, swirl, and mix together.
What You Need
Whole or 2% milk
Blue and yellow food coloring
Bowl or pie plate
Dishwashing soap
Toothpicks
What to Do
Ask the children to pour some milk into the bowl. Have them place
approximately 2 drops of blue and 2 drops of yellow food coloring
in various spots on the surface of the milk. Dip the toothpick
into the soap. Gently touch the soapy toothpick to each of the
blue and yellow drops. What happens? What do you see?
Vocabulary
Current: A flow of water or air
Liquid: Feels wet, takes on the shape of the container it is in.
Liquids flow.
Molecule: The smallest particle of a substance that retains all
the properties of the substance. Single molecules are too small
to be seen.
Surface tension: Water (H2O) molecules tend to stick together
because of weak bonds between the hydrogen atoms and oxygen atoms
of different water molecules. A water molecule in the center of
a drop is pulled equally in all directions by these forces. For
a molecule on the surface of a water drop, the situation is different.
Since there is no liquid water beyond the surface, there is no
corresponding pull outward for each pull in, and the bonds with
other water molecules pull the surface molecules back into the
drop. The pull of those bonds makes the water molecules at the
surface behave like stretchy skin, a phenomenon known as surface
tension.
Swirl: The motion of twisting or whirling
Try This
Add different amounts of soap. How does this affect the food coloring?
What if you tried different soaps?
Do the exploration with other colors. What do you think the results
will be?
What would happen if you used paint instead of food coloring?
Try using other liquids such as water or juice. What happens?
What other liquids would the children like to try?
Can the children move their bodies to demonstrate what happens
to the drops of color?
Can they draw pictures of the exploration?
|
