Providing children with a variety of objects during tubby time can hone their observational and predicting skills while introducing the scientific concept of flotation. Give the young child objects one at a time and ask if the object will sink or float. Have the child predict the behavior of each object and then place it on one of two piles on the bathmat beside the tub -- sinkers and floaters. Hand the objects to the child one by one to test. Talk about the results together.
Draw a line down the center of chart paper. At the top of each column place the words "sink" and "float." Allow the children to actively test a variety of objects such as feathers, pebbles, paper, metal bottle caps, sponges, marbles and pieces of cork by placing them gently into the water table. Record what happened to each object by having the student who tested it draw a picture of the object under the appropriate column.
Have students form shapes from modeling clay such as Play-Doh. Test the shapes to see whether they sink or float. Use spheres, cubes, tubes and finally boat-shaped clay. Record the results on chart paper as in Section 2. Ask the children to create a shape that they predict will float and another that they think will sink. Have the children draw or paint their shapes on paper. Create a bulletin board display of shapes that floated and a separate section to display shapes that sank.
Ask the children to look at the chart paper or bulletin board displays that are recording the results of their experimentation. Discuss together why some objects floated while others sank. What shapes made the best floaters? What shapes led to objects sinking? Provide felt board pictures of other everyday things that float and of those that sink. Have the students place the pictures on the felt board under columns titled "sink" and "float." Discuss what was learned.