Have students work in pairs or small groups to experiment what happens to the ball if you spin it faster or slower, make bigger circles, or what else they can spin in the jar. Have them make predictions, then record their findings.
For a an extension to this activity students could drop the ball from three predetermined heights, record the height of the first bounce, and then predict the height of the first bounce for a fourth starting height.
Students who finish early could try drawing the structures of blood. If the teacher can obtain the materials, looking through a microscope at real slides of blood and draw that for a further extension.
This activity lets students create a simple and safe model of human blood. It provides a way to make something microscopic easier for children to understand.