Hovercraft

Warning!- Adult supervision: choking hazards

Materials

  • Blank CD
  • Science Stickers
  • Wooden Spool
  • Roll of Duct Tape
  • Large Balloon
  • Individually Wrapped Straw

Procedure

  1. Place the spool on top of the center of the CD, and secure it to the CD with duct tape. Ensure that there are no gaps to form a complete seal.
  2. Stretch out the balloon or blow it up and let the air out.
  3. Use the duct tape to secure the opening of the balloon around the top of the spool. Ensure that there are no gaps once again.
  4. Decorate the top of the CD with the science stickers or any additional decorations that you have available.
  5. Remove the straw from the wrapper and place it through the hole in the bottom of the CD and the spool. Blow into the end of the straw to fill up the balloon with air.
  6. Pinch the balloon so the air cannot escape, and remove the straw from the hovercraft.
  7. Place the hovercraft on the table and release the air from the balloon. As the air is escaping, it glides across the table!

Science Behind it!

Hovercrafts move by ‘floating’ on a thin layer of air. This hovercraft works by keeping a supply of air in the balloon and releasing it slowly through a small hole. When the air is released from the balloon, it travels in all directions beneath the CD. This ‘cushion’ of air reduces the force of friction between the hovercraft and the surface it is floating on. Friction is the force that slows down objects when they are in contact with one another. For example, when pushing a heavy piece of furniture across the floor, there is strong friction between the furniture and the floor, so it is difficult to keep it moving. However, when a hockey puck is sliding across ice, it remains in motion for a long time, since the friction between the puck and the ice is very low.
Scientists at NASA use hovercraft to test the motion of spacecraft. This is because objects in space experience very low friction. Can you think of any other examples of situations in which friction would be high or low? What are some other ways that friction can be reduced?

Based on your answers to the previous questions, can you modify this design to work even better?