Tubs of water (one for every pair of children)
Small items that will float
Small items that will sink
Fill tubs with water. Gather float and sink items, and sort them into bowls or containers.
Give each pair of children a tub of water, and tell them they are going to test several things to see if they will float or sink. Pass each child a bottle cap, and ask them to make a prediction whether they think the cap will float or sink. Ask them to place the bottle cap in the water to see what happens. Have children test each of the items in the same manner, making a prediction first, then testing them. Do not pass out all of the items at once; instead, pass them out one at a time, randomly. Each child gets their own item to test in the water, but each pair of children shares a tub of water.
Examples of things that sink:
Toy fish (like a math manipulative fish)
Examples of things that float:
Small piece of paper