To demonstrate liquefaction, you will need the following materials:
cornstarch
water
bowl with lid
marbles
1) Mix water with the cornstarch until you get a smooth mixture. It should still be stiff and not runny. After mixing, make a ball with the mixture. You can break the ball apart and observe what happens. It will start out looking dry, but then in a few seconds, it will begin to look runny.
2) Make a thick pancake-like form and place it on the lid of the bowl. Place a marble on top of the pancake. Begin tapping the sides of the lid to make an "earthquake". Observe what happens to the marble. This happens to houses and people during earthquakes. They sink into the ground and when the earth stops shaking, they are stuck.
WHY? The second observation demonstrates what happens in an actual earthquake where clays are involved. When seen under a microscope, most clays have a "house of cards" structure. Water gets trapped within the pore spaces. When shaken, as during and earthquake, the water is forced out and to the surface and the clay layers become stacked. This is known as liquefaction.
Students have fun playing with the "clay".
What a mess!! Mrs. Jordan has to love it when I visit.
