Use the following instructions to create a simple scale that will allow students to think about their
rocks in terms of lightness or heaviness
Using duct tape, tape one end of a yard stick onto a table top. Tie two pieces of string to the top edges of a strawberry basket, so that they criss-cross at the middle point. (This allows the basket to hang evenly). Before knotting the string, thread the string ends through a large, sturdy rubber band. Once done, the rubber band should be in the center, where the strings criss-cross. Use duct tape to attach the rubber band to the end of the yardstick. The basket should now hang down from the yardstick.
Students will be able to put rocks into the basket. Heavy ones will make the basket hang down low, while light rocks won’t. From the edge of the table, hang a piece of newsprint. Write “light” on the top portion of the paper and “heavy” on the bottom portion (see example below). Draw a line to visually divide the top and bottom. This paper will be directly behind the basket, so that students will now be able to weigh their rocks and determine whether their rocks are light or heavy. (Hint: Make the string pieces long enough to allow room for students to place rocks in the basket. Also, this scale works well with a number of different items.
Think about making one for a more permanent part of the classroom to allow for spontaneous, student-initiated weighing.)
This teacher sheet is a part of the Rock Hunters lesson.