I feel like we've talked about earthquakes a billion times, but (to my children at least) it never seems to get old! :)
This time we did a liquefaction demonstration. You fill up a big container with sand, then stir in water until the sand is quite saturated. This represents your groundwater. You can also add blocks to represent buildings, for dramatic effect. :)
Then you shake your container vigorously. The sand becomes suspended in the water, and the area is temporarily liquefied. You can read more about it here.
