Just wait until you experience
"blowing up" a balloon!
The exploding balloons demonstrate that nothing can be taken for
granted in science. If you buy a balloon from a vendor, itŐs probably
filled with helium. Helium is a gas like air; in fact, air has some
helium in it. But helium is lighter than air. If you take the same
volume of air and helium and weight them on a scale, the helium will
weight less. This is because helium is less dense. Because helium is
lighter than air, a helium balloon rises. Hydrogen is another gas
lighter than air; it is even lighter than helium. Hydrogen is not used
in balloons and this demonstration shows why.
Helium is a special gas called a Noble Gas, which means it doesnŐt
burn. When a match is held near a helium-filled balloon, the balloon
pops. ThatŐs it. But when a match is held near a hydrogen-filled
balloon: BOOM! a real explosion. This is because hydrogen burns very
easily. It combines with oxygen to make water vapor. Even though both
balloons look the same from the outside, there may be something very
different on the inside.
Link to Teacher Resources
Page Updated 8/29/08