The younger Free-Ride offspring’s class is apparently just about to move on from sediment-related issues and start a new science unit. Indeed, this week they even did an experiment as a preview of the new unit, which the younger Free-Ride offspring recounts with these four panels:
“First, blow up a balloon and tie it.”
“Then rub a wool cloth on it.”
“Finally, rub it against a wood cabinet.”
“And it stayes up.”
* * * * *
So, clearly the experiment was about static electricity, and we can look forward to more content on electricity (and probably magnetism) in the coming unit. And, I’m hopeful that there will be detailed discussion of some of the underlying physical structure that leads to these fun regularities in nature.
For instance, it would be cool if they talked about why charging a balloon enough to get it to cling to the cabinet or wall seems to be easier in winter. Why should cold, dry weather be better for generating a charge separation than warm, wet weather?
Using the wool cloth (as opposed to the hair on your head, like we did when I was a kid) is pretty fancy. If they examine the permutations of wool cloths and silk cloths rubbing glass rods and rubber rods, dare I hope that there will be some discussion of why certain materials are better at grabbing up electrons and others are better at depositing them?
(And just now, I’m wondering whether it’s a safe assumption that the fourth grade science class will even discuss electrons in the context of electricity.)
Also, why, in the fourth panel, does my childe spelle like Isaac Newton?
Love the four panel description! My guess is probably 50-50 whether electrons and other physical structures will be addressed but I’m with you in hoping that they are. Electicity is such a rich conceptual area for kids.
Why do you need to blow up the balloon?
What an interesting question. I always assumed that aside from the theater, it created more buoyancy, allowing it to stay up more easily.
My educated guess is that it lowers the overall density of the balloon, making it stick easier.
That is, an air-filled balloon has roughly the same mass as a deflated balloon, but a much larger volume, lessening the density of the balloon. This would make it easier to “float” while stuck to an object.
Note that this is a simple hypothesis on my part, but it should be relatively easy to gather data on it!
My guess is that it involves charge density more than mass density. With more surface area on an inflated balloon, you can get more charge on the same mass.
Your childe is very smarte!