Activity : Have the kids relax. Palms down on the desktop. Feet flat on the floor. Eyes closed. Utterly relaxed. Wait for total and absolute quiet. Here's where I climb up on my front LAB desk and drop a 12 pound indoor shot put to the floor from a height of about 10 feet or so. The resounding rattle is felt by all students in and out of the class! Without seatbelts the 1st row of kids usually fall out of their seats... (The music teacher, whose class is one floor below mine, just loves me! Thank Newton for tenure, eh?)
Analysis : The kids closest to the "epicenter", my desk, should have felt the brunt of the force. If they paid real close attention, they can even tell the difference in the timing of the feelings from their feet to their hands! The kids in the back heard it more than felt it, but still feel it. The kids in the hallway actually feel it BEFORE they hear it! Gee, I wonder why... This leads into a discussion of the way earthquake energy travels. Try this with several different objects and repeat each object several times. Upon comparing notes and observations, the kids can actually construct a map of the location of the "epicenter", the teacher desk in this case, due to each students recorded effects.
NOTE : I use an indoor shot put for this because it harms the floor less than alot of my other "drop" things I use in Fizzix class. I have also used bowling balls - you'd be amazed at a bowling ball's bounce-ability! Tackling dummies, punching bags or the old medicine balls borrowed from your Phys Ed Dept or the local gym will work, too.
See also, my Earthquake Waves, the story about P, S, Love and Raleigh Waves!