72 Starting off the new year with a lab. This is a coffee filter drop lab, in which students model the motion of a coffee filter from data they take in class, then they predict how high they would have to drop it from in order for the filter to take a given amount of time to hit the floor. The tricky bit is the room is less than 3 meters tall, and invariably they calculate a height greater than 3 meters (I’m sneaky about how I pick the “given” times). We have to go out to one of the stairwells to test the prediction. A good model results in a drop time within 0.1 s of the given time.