Seismographs detect miniscule tremors in the earth's crust, indicating where and when earthquakes occur. Though modern instruments are digital and very sensitive, they are not the first seismographs to exist. The Chinese, according to Science in School, developed a seismograph made of a brass bell with a stiff clapper inside. The clapper held eight pins gently against the back sides of eight dragon-shaped spouts positioned around the bell. When the earth shook, the stiff clapper trembled, tapping one of the needles against the one of the dragon spouts. Marbles fell out of the dragon's mouth, indicating an earthquake's location and severity.
Turn your flare-rimmed plastic flower pot upside-down and drill four holes in it about 3 inches from the bottom. If you connect the holes with a straight line, they should create a square. Though the original had eight holes, the homemade version just needs the four cardinal directions.
Cut your plastic pipe into four 3-inch pieces and one 5-inch piece with a high-speed rotary tool. Set the longest plastic piece aside.
Glue the four pipe caps onto one end of each 3-inch pipe piece. Turn each piece so you can see the open end.
Draw a thick bead of hot glue along one edge of the opening, creating a very shallow barrier. This will keep the marbles in place, but won't prevent them from shaking loose. Allow the hot glue to dry for 10 minutes.
Slip one 3-inch-pipe piece through each hole in the flower pot, angling them very slightly. Hot glue the pieces into place one at a time, holding each one until the glue is dry enough that the pipes don't move.
Drill four 1/8-inch-diameter holes about ½ inch from one end of the 6-inch-pipe piece. Snip 3 inches from the sharpened end of four bamboo skewers and slip one into each hole, creating a plus sign at the bottom of the pipe.
Slide the pipe up into the flower pot and up through the drain hole, positioning the skewers against the ends of the pipes. The skewers should just touch the pipes, not sit rigidly against them. Hot glue the 6-inch pipe into place at the drain hole, letting it dry for 10 minutes.
Spray paint the entire assembly hammered bronze. Let the spray paint dry 2 hours and paint the four marble spouts with green and white paint to look like dragons. Let the paint cure fully overnight.
Place one small, wooden bowl below the mouth of each dragon. Slip several marbles into each dragon's mouth.
Bang on the table the seismograph sits on, positioning yourself at different sides of the seismograph. If it works, the marbles should fall from the dragon facing you.
