8th Grade Science Project on Tectonic Plates

Research

• Any science experiment follows a way of determining accurate information. This is done through the scientific method. It includes five categories of investigation: purpose, research, hypothesis, the experiment and its conclusions. In the case of a project involving plate tectonics, eighth grade students' first step of the experiment could include research on what the earthquake machine represents as a scientific concept. Ask questions about why certain tectonic plates and faults create bigger earthquakes.

Hypothesis of Earthquakes

• The tentative answer to why certain tectonic plates produce bigger earthquakes is posed to the project as a hypothesis, which is a guess that can be proved or disproved by the experiment. The hypothesis of the earthquake machine could include the answer that bigger earthquakes occur because of variables like incline of the fault and the amount of energy released. The students will learn about elastic rebound and how energy is stored and released using a block of wood which is the object being acted upon, and the pulling of rubber bands, which represents the elastic force that creates an earthquake.

The Earthquake Machine Experiment

• Fold 120-grit sandpaper in half lengthwise and cut it to make eight strips of sandpaper. Wrap one of the strips around a 6x6 one-inch-thick block of wood and hold it in place with rubber bands stretched horizontally over the block. Tape the seven remaining strips in one long strip and attach the sandpaper lengthwise along the center of a 6x6 board, using two thumbtacks at both ends. Attach a paper clip to the horizontal band that holds the sandpaper on the block. Tie one end of a string to another paper clip and attach the block to the paper clip on the string. Tie the loose end of the string around a dowel of wood. Place the block on the center of the sandpaper strip at one end of the board.

What Will Happen?

• The box will move with starts and stops, which you can record by distance from the last. Divide this data by the number of lurches of the wood to calculate an average stop and start. Students can add small rocks or bricks to the block of wood or add more rubber bands to change the model. You can change the grit of sandpaper as well as the incline of the board, and collect different data of each of the variables.

Conclusions

• The data collected through observation and measurement allows students to draw conclusions of the experiment. They can summarize the data to see if it corresponds to the hypothesis of the experiment. What does the number of rubber bands, which represents different amounts of energy released, the angle of the board, which represents the incline of the fault, and the sandpaper grit, the difference of force to move the fault, tell about tectonic plates and earthquakes? It may be that different tectonic plates and faults store different amounts of energy and make larger earthquakes and that variables of surface topography influence the magnitude of earthquakes.