My husband Neil and I have a longstanding interest in encouraging children to read and write and to mess around with science. When we lived in Colorado Springs, for instance, I occasionally met with the teen writing group at the local library to pass on information, such as how to write a query letter, and to help them critique each other's writing. Also, Neil was a volunteer science fair judge. So, when the Summit County Library System initiated it's "Fizz Boom Read!!" summer reading program this year to encourage children to both read and explore science, we were happy to sign up as volunteers. On July 9th, we manned two of ten science stations at the Frisco library that engaged children in experiments with air pressure.
You can see a lot of photos from that day HERE, but I borrowed a few photos from the site that featured Neil or myself to share with my blog readers. In the first photo below, two smart young gals who previously had manned the marshmallow experiment station at another library location are explaining to me how the experiment works while I read the instructions. In the second photo, we're running the experiment with some excited kids (notice the plunger for demonstrating a vacuum). So, what do you think happens to a marshmallow inside of a bell jar as you remove the air around it with a vacuum pump?
Here's the answer: the marshmallow expands in size. As you suck air out of the jar, there's less air
pressing on the outside of the marshmallow to hold it's shape and the
air on the inside of the marshmallow presses against the outer edge,
expanding it. Because the jars were inexpensive
and the kids weren't that strong with the pump, they couldn't get ALL
of the air out of the jar and make the marshmallows explode. They just
saw them grow. Then when they pulled the hose to the vacuum pump off the
bell jar, allowing air to rush back into it through the hole, the
marshmallow collapsed, often to a size that was smaller than it was
starting out. Pretty cool little experiment, and the kids got to eat the
shrunken marshmallow to boot!
Below are two photos of Neil working at the "Balloon Zipline" experiment station. You blew up a balloon, fastened it to a straw on a line, then released the air from the balloon and let go of it to see if the force of the air leaving the balloon would propel it along the line.
It was a fun day for us, and I hope the kids learned some things from the hands-on experimentation!
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