Sink? or Float?

This experiment will allow you to think about why some things sink in water and why others float.

What you need:

• Large plastic tub (clear works best)
  
• Water
  
• A variety of items (enough for 1 for each child) such as:
  • an orange
  • plastic action figures
  • toy boat
    
  • dinkie car
    
  • ball of aluminum foil
    
  • rubber ball
    
  • empty drink container (water bottle)
    
  • a coin
  • playdough (2 equal sized pieces, 1 rolled in a ball and 1 flattened out)
    

Instructions:

1. Allow the children to choose an item to place in the water.
   
2. Before they put their items in the water, ask each child to guess whether her item will sink or float.
   
3. Drop the items one at a time into the water.
   
4. Why do some sink, and some float?
   
5. Why does the ball of playdough sink and the flattened piece float?