1 class periods of 45 minutes each
Thinking & Reasoning
Using a candy bar, gum, and Twizzlers, students will demonstrate the effects of deformational forces on the earth's crust.
Crustal deformation depends on two things, the type of rock layers (strata) and the type of deformational forces. There are probably as many different rock layers as there are different candy bars. Candy behaves like many rock layers, each layer having its own distinct traits.
There are three basic deformational forces: tensional, compressional, and transversal. Tensional forces are forces that pull crustal rocks apart. Compressional forces are forces that squeeze crustal rock together. Transversal forces are forces that push crustal rock horizontally and in different directions.
In some cases crustal rocks move in the same direction but at different velocities. These forces translate into faults, folds, and joints. Faults are breaks or cracks along which crustal rocks move. Folds occur when compressional forces are applied to rock that is hot and pliable. Anticlines are folds in rocks that bend upwards. Synclines are folds in rocks that bend downwards. Joints are parallel cracks in rocks. All of these physical features can be seen in broken and bent candy. Have the students bring in their favorite candy bars and the other items.
(NOTE: At the end of this lesson, the participants will be able to consume more than just the wealth of new knowledge gained by this activity.)
Review vocabulary: crustal deformation, tensional forces, compressional forces, transversal forces, faults, folds, joints, anticline, syncline. Pair all students. Give the students the following instructions:
1. Unwrap one gum piece and apply compressional forces with your fingers on the gum. Record your observations.
2. Reshape gum piece and apply a tensional force with your fingers on the gum. Record your observations.
3. Unwrap second piece of gum and apply a transversal force with your finger on the gum. Record your observations.
4. This time, using your candy bar, repeat Step 3. Leave your candy bar on the napkin. Observe the effects of tensional forces on different candy bars by looking at the candy bars of at least five other students. Record your observations on five different candy bars.
5. Take your Twizzlers and stack them horizontally on top of each other, supporting them with your hands. Apply compressional forces by pushing in towards the center. Observe and illustrate your anticline and syncline.
6. Closure: Clean up any mess on your desk. Hand in your observation sheet and enjoy your candy.
Activity - Find web sites on the Internet that deal with this subject. Find interactive sites that teach students these concepts. Report findings to the class.
Show students candy bars that have been deformed by various types of forces. Ask students to identify the type of force that caused each deformation.