Earthquake Machine

Last month, the grade 5 class at my school was doing a unit on natural disasters. I offered to make an earthquake simulator, so the students could build and test earthquake-proof structures. In our original plan, the students would use wood sticks and play-dough, but I think it became a homework assignment, and as a result the students were encouraged to use whichever materials they wished.

earthquake

The earthquake table is simple in design. It is a cafeteria tray with holes drilled into the corners, suspended from a frame using small springs. In this case, I used a cart, but I think I’ll flip a table upside-down next time to make it a bit more stable. I use a hand drill to move the table. A ribbon is tied to the table, and loops around a custom-made drill bit. The drill bit has two axes, offset by about two centimeters. This provides an oscillation to the table, with the direction of the motion (ie: s- and p-waves) depending on where I hold the drill.

An improvement would be to make a mount for the drill. I found it shaking in my hand, and so it was tough to ensure the vibration went undamped into the system. The variable speed of the drill made it a bit tricky to find the resonances, too.

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