# Science Lab: How Does Stress Cause Movement Along Faults?

By Marlene Gundlach

A fracture becomes a fault when the rocks on either side of a fracture move in relation to each other. This lab will demonstrate how stress causes this movement along fault lines.

## Prelab Discussion

Planning earth science projects is a great way to give students hands-on experience and help with comprehension.

Ask students to read the entire activity, and then discuss these points before beginning:

• Review the differece between tension and compression.
• Give some specific examples of the types of faults being modeled.
• Have students explain what each of the following is modeling: cardboard pieces, boundaries between pieces, the student (blocks of crust, faults, stress forces).

## Materials and Preparation

The students will need the following to complete the lab:

• Sheet of corrugated cardboard
• Scissors
• Pencil
• Paper
• Metric Ruler
Cut out two pieces of cardboard to match the five shape in this figure. Each piece should be about 6 cm tall. Together they should from a straight line about 25 cm long. Label the shapes with letters as shown in the figure.

Time to complete lab: about 30 minutes.

## Procedure

Give each student a copy of the table to record their observations and measurements from the activity.

1. On a flat surface, fit the cardboard pieces together as shown in the figure to the right. Move the pieces together to remove gaps.
2. Measure the total lenght of the assembled pieces, from the left edge of first A piece to the right edge of the last A piece. Record this measurement in both boxes of the first column of the data table.
3. Model normal fault movement by sliding all three A pieces down about 1 cm in relation to the B pieces.
4. Measure the total lengthh of the assembled pieces and record this measurement in the correct column in the data table.
5. Model reverse fault movement by moving the A pieces up about 1 cm in relation to the B pieces.
6. Measure the total lengthh of the assembled pieces and record this measurement in the correct column in the data table.