Instruct them to lightly strike the tabletop on its front edge and observe the water. Have them draw pictures of the waves in the box. Repeat twice more, lightly striking the top of the table, then the side edge. Tell students that these are the three directions in which earthquake waves vibrate. Ask them to report on which one produced the biggest wave.
L waves cause the most damage and set up tsunamis.
Use the next activity to reinforce the first one. Use a slinky toy or a large, weak spring to show the three earthquake wave motions. Students will work in pairs. Direct the students to stretch the spring to about six to 10 times its compressed size. One student should be at either end.