Summary: Balloons filled with different gasses are observed and described before and after being touched with a burning candle.
Hazards: Before doing the experiement, let the students know the balloons can be quite loud.
NEVER, under any circumstances, transport balloons with hydrogen or hydrogen + oxygen in your car.
Hydrogen is flammable.
Chemicals and Solutions:
Candle on Stick
Ten foot pointer with candle taped to one end
Fill 3 balloons of the same color. Fill one balloon with helium (or oxygen), another with hydrogen, another with a mix of hydrogen (2/3) and oxygen (1/3). Use fishing line and duct tape to suspend the balloons about 10 feet in the air and at least 3 feet apart, either from the floor or from a table or lab bench.
The balloons are ignited with the candle attached to the pointer.
AUTION: The 2:1 mixture is very loud!!! and can shake the rafters.
Discussion: First, students are asked to describe the balloons. Then, each balloon is popped using the candle on the pointer. Students are asked to observe and describe each event. Students are then asked to theorize about the balloons.