Tackle
the science portion first. Fill your chosen vessel (we used glass
measuring cups and mason jars) about two-thirds full of water. Add a
puffy layer of shaving cream on top. Explain that the water represents
air and the shaving cream represents a cloud, which is made up of lots
of tiny droplets of water or ice. Mix some of the blue food coloring
with water and add it, a few drops at a time, to the top of the shaving
cream.
The result will be blue rain. For faster rain, try non-diluted
food coloring.
Now it’s time for some hypothesizing. Ask your children to think
about why clouds are able to float. (The short answer is that the water
and ice droplets are very light.) Why does your child think clouds
sometimes make rain? You can keep the answer to this one simple, too.
The bigger the cloud gets, the more the water droplets bang together and
grow. Eventually they get so heavy, they fall to the ground.
Challenge older kids to flex their critical thinking skills a bit
more. The truth is, nobody knows exactly how clouds make rain.
Scientists think it has to do with the water droplets freezing onto tiny
particles of dust or bacteria inside the cloud, called cloud seeds,
causing them to become heavy and fall to the ground. If you really want
to blow your kiddos’ minds, mention that people sometimes try to make
it rain by sending planes to shoot dust into clouds, a process known as cloud seeding.
At
this point, your children will be pretty antsy to take a crack at
making rain. Hand over the dropper and let them try it. We used a
leftover medicine dispenser instead of a traditional dropper. Since my
three-year-old son pushed quite a bit harder than I did, he was able to
observe the effects of varying amounts of pressure on the shaving cream
and water.
What I like about this technique is that, for the most part, the colors stay separate on top of the shaving cream.
But
below the shaving cream, they swirl and mix together to create
beautiful new hues. Seeing blue and red on top and purple underneath
really reinforces the color mixing concept.
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