Background: This lesson is intended to be used as part of a unit or in conjunction with other lessons on weathering and erosion. It assumes that students have already been introduced to weathering and that they understand that there are two forms of weathering: physical (also referred to as mechanical or chemical). As students complete these activities, they will learn more about what happens during each type of weathering. In physical weathering, rocks are broken down into smaller pieces without changing their chemical makeup – tearing a piece of paper into smaller pieces. An example of physical weathering would be a cracked sidewalk. In chemical weathering, rocks are broken down by chemical actions that change their makeup – burning a piece of paper and having it change into ashes. An example of chemical weathering is rust on outdoor furniture. The activities in this lesson follow the scientific method; therefore, students should be familiar with its steps.
Preparation: Before beginning, the teacher will need to prepare a set of colored index cards (or construction paper cut to card size) to be used for grouping. You will need 4 cards each of 5-6 different colors (depending on the number of students). In the upper left of each card, write a number from 1-4; in the upper right, write a letter from A-D; in the lower left, draw a shape (circle, triangle, square, or rectangle); and in the lower right, write a direction (north, south, east, or west). Vary the way the cards are set up – for example, all of the red cards should not have the same numbers, letters, or shapes, etc. The cards may be laminated for durability.
After passing out the cards, you can then quickly group and/or regroup students by color, number, shape, letter, or direction.