Materials
A variety of rocks with numbers printed on them A bucket balance scale
Counting blocks or bears A piece of paper with two columns
Instructions
1. In advance, prepare a chart on the piece of paper. In the left-hand column, draw a picture of each rock with its number on it. Leave the right-hand column blank so that the child can fill in the number of counters they need to make the scale even.
2. The teacher introduces the use of the balance scale and the care that must be taken with it. If necessary, demonstrate the experiment.
3. A child chooses a rock and places it on one side of the scale. On the other side of the scale, the child places the counting blocks or bears until the scale balances.
4. The child then counts the number of blocks he used and writes the number down in the righthand column next to the appropriate rock picture. In turn, the children complete the activity with all of the rocks.
5. Later the teacher can gather the children's data on a graph and then do the activity again to check all of the data.More to doMore science: Organize or rate the rocks according to weight or size. * Include a pumice rock with other rocks of different sizes and materials to study the speed of sinking in water or to see whether any rocks float.
