• Helium balloonsBallons am Himmel image by Jens Hilberger from Fotolia.com
  
  Helium balloons brighten birthday parties in the classroom, but they can also be used as the basis for several experiments. Help students understand more about the effects of different gasses by using helium in different experiments and science projects.
  
  

Shrinking Balloons

• Start with five balloons: one Mylar and four regular balloons. Fill three with helium, including the Mylar balloon, and two with air. Put an air-filled balloon and the helium balloon in the freezer, the leave the rest in the room. Keep track of the air loss of all of the balloons by measuring them and keeping logs. In one experiment by a middle school in California, the balloons in the room lost the most air, while the helium balloon in the freezer shrank more than the air-filled balloon. The Mylar balloon did not change.
  
  

Helium Balloon in the Bus

• Fill a balloon with helium and fasten it to the floor by tying it to a brick or cinder block with enough slack in the string so the balloon can move around a little. Have the students observe the balloon as the bus driver drives the bus around the neighborhood, going around turns and changing the rate of speed. The students should record any movement the balloon makes. When the bus speeds up, the helium balloon goes forward and as the bus slows, the balloon goes backward. This experiment allows the students to observe that because the balloon is filled with helium and not air, its lighter weight allows the balloon to decelerate or accelerate more slowly than if it were filled with air.
  
  

Inhaling Helium

• Experiment to discover the affect of helium on the human voice. Fill a balloon with helium and inhale a little of the gas. The helium will affect the pitch of your voice. This is because helium is lighter and less dense, the pitch of your voice will rise. Because air that you breathe is denser, the pitch of your voice is lower.