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Demonstrations › Properties of Gases

Lecture Demonstrations

Properties of Gases

A small amount of water is heated to boiling in a metal can (aluminum soda can or large 20 L solvent drum) filling it with water vapor. The can is removed from heat and sealed. The can will collapse quickly and dramatically.

 

Various experiments are performed with liquid nitrogen.

 

A large soft drink bottle contains water and a small medicine dropper at the top. As the sides of the bottle are pushed, the dropper sinks to the bottom. When the pressure is released, the dropper rises to the top again.

 

A heat gun or hair dryer is used to inflate a large plastic garbage bag. The hot air in the bag will have more energy than the air in the outside of the bag, increasing the collisions on the inner surface of the bag and thus increasing the pressure causing it to float in air.

 

When a spark is introduced to a container full of ethanol vapor, the vapor explodes. Because the container is closed, the rapid increase in heat and pressure blows the stopper off of the container and produces a loud bang.

 

A metal pipe is held vertically and one end is heated with a burner for about 10 to 15 seconds. The vertical pipe will produce a loud tone for as much as 30 seconds.

 

A small amount of water is injected into a sealed, inverted round bottom flask that is connected by tubing to two reservoirs below. Moments later, the liquid from the reservoirs flows up into the flask, creating a fountain effect. As the two liquids mix, they begin to emit a blue chemiluminescent glow that persists for 1 to 2 minutes.

 

The relationship between pressure and volume is explored with the Vernier Gas Pressure Sensor. Data is displayed on the laptop using the Logger Pro program

 

The relationship between pressure of a gas and temperature is explored using the pressure sensor. Data is displayed using the Logger Pro program.

 

The relationship between vapor pressure of a liquid and temperature is explored using the pressure sensor. Data is displayed using the Logger Pro program.

 

Two balloons, one filled with H2 and the other with He are ignited with a hot pinor lit splint, with different results.

 

Calcium carbide is added to water in a balloon. The acetylene gas produced in the reaction is ignited producing a loud explosion.

 

A piece of copper foil is suspended above a container containing acetone. The copper wire will continue to glow red hot suspended above the liquid.

 

When a volume of confined gas is rapidly compressed, enough heat is produced to initiate the combustion of flammable materials.