So, earthquakes, right? Not everybody has experienced one, but chances are good that all your students at least know what they are. The not-so-big one in Oregon in ’62 is the first earthquake I remember hearing about, as it partially knocked over my grandparents’ chimney. Kids may be familiar with the idea of an earthquake’s epicenter and, by extension, the seismic waves that extend outward from that epicenter. With this handy dandy Demo Science science demo, you can give your students first-hand experience with seismic waves. On a significantly reduced scale, of course.
Make A Fake Quake
Since earthquakes are pretty much impossible to predict, and because, even if they weren’t, intentionally bringing a bunch of schoolchildren into an earthquake would probably be frowned upon by just about everyone, you’ll have to create your own faux-quake. Or maybe a quasi-quake. I don’t know.
Anyway, you’ll need some flat (or flattened) cardboard, at least four or five decently thick sheets, and a bowling ball—or a large rock roughly the size and weight of a bowling ball. Stack the cardboard flats on the floor of your classroom in front of your desk. Ask for volunteers, or just pick random kids (NOT Kevin), to “assist” you: have some of them stand in the corners of the room, send one kid to stand just outside the door of the classroom, and send one kid down the hall a ways, say two or three doors down.
With your volunteers in place, instruct the remaining students to place their hands flat on their desks and their feet firmly on the floor, and to remain quiet and still. Give your standing volunteers the same notes re: their feet and shutting up.
Now, the easiest part. Stand up on your desk, lift your bowling ball or rock, and hold it over the cardboard. Then, just drop it. This might potentially make a bit of a ruckus, so be sure to let your fellow teachers in surrounding classrooms know what you’re up to, lest the sudden noise cause anyone to soil their trousers. Also, maybe make sure the janitor is cool with you dropping a 12-pound rock–or whatever you’re using–onto the floor.
(If the janitor or principal is being a jerk and won’t let you perform this experiment indoors, you could set up a modular room out in the playground and use that. See United Partition, for example, for examples of modular rooms–they’re quite peculiar things.)
The Science of Dropping A Bowling Ball in the Middle of A Classroom
Upon hitting the ground, your bowling ball caused vibrations that are analogous to seismic waves. Ask students what they felt from their various locations. Discuss who felt the impact the strongest, how far away it could be felt, and why.
Obviously, those students closest to the drop will have felt it more than the kids in the corners of the room. Did the kid in the hall feel it at all? Why is the impact more strongly felt in some places than others