Mad Science of West New Jersey - Make-a-Quake Experiment

What you need:
• A Friend
• Cardboard box
• Modeling clay
• Paper
• Pencil
• Ruler
• Scissors
• Small rocks or marbles
• Styrofoam or plastic cup
(Styrofoam is easier)
• String
• Thin felt marker

What you do:
Step 1: Cut the top flaps off the box.
Step 2: Set the box on its side. Poke two holes about 4 cm (1.5") apart at the top of the box.
Step 3: Cut an 11 cm (4") wide slit about 4 cm (1.5") from the edge of the bottom of the box.
Step 4: Poke two holes on opposite sides of the cup, just below the rim. Poke one hole at the bottom of the cup with your pencil.
Step 5: Cut two pieces of string as long as the box’s height.
Step 6: Tie the end of a string through each rim hole on the cup.
Step 7: Press some clay into the bottom of the cup.
Step 8: Uncap the marker and push it through the clay until its tip sticks out of the hole in the bottom of the cup. Fill the cup with the small rocks or marbles.
Step 9: Make a cup holder at the top of your box. Cut a triangular slit into the top and place the cup on top. The marker tip sticks
through the slit!
Step 10: Hang the cup inside the box. Thread the string ends through the holes at the top. Pull the strings until the hanging cup’s marker just touches the bottom of the box. Tie a knot in the strings at this length.
Step 11: Cut the paper in half lengthwise to make a long, thin strip.
Step 12: Make a second cup holder at the top middle edge of your box. Set your cup on top.
Step 13: Slide the tip of the paper through the bottom slit. Hide the rest of the paper behind the two flaps inside the box. Let the cup hang so the marker just touches the paper.
Step 14: Have your friend shake the table or the box. Slowly pull the tip of the paper. The marker draws a line on the moving paper. What does the line look like? Change places with your friend. What does the line look like now?

What's happening?
You built a seismograph! Seismo is a Greek word that means shaking. Graph means written or drawn. A seismograph records vibrations made by the Earth’s surface. Vibrations can be natural or man-made. The Earth’s surface is made of layers called tectonic plates. When the plates shift, they make vibrations. Miners may use explosives to dig into the earth. This also makes vibrations. We see these vibrations on the seismograph. When the Earth shakes, it causes the bottom of the seismograph to shake as well. The marker doesn’t move but the paper on the graph does. The marker draws a wavy line because the paper shakes. Shaking the box more is like making a bigger earthquake. It causes bigger waves on the paper. The marker draws a straight line when the paper does not shake.

Now try this!
The line drawn depends on the type of earthquake. What do the lines look like when you pound on the table instead of shaking it?