Thursday, May 20, 2010
Ideal Gas Law with a Balloon
The ideal gas law is basically a combination of a bunch of scientific laws relating to gases. It's stated as:
PV = nRT
P = pressure
V = volume
n = number of moles* of the gas
R = a constant (no need to worry about its value for our purposes)
T = temperature
In order to keep any equation balanced, if you change one thing in the equation, something else will change to compensate.
Here are some examples:
If you increase the number of moles of the gas, the volume it takes up will increase.
If you increase the pressure on the gas, the volume will decrease.
If you increase the temperature of the gas, the volume it takes up will incrase.
A balloon does a lovely job of containing a gas. Use one to demonstrate these properties of gases.
-Increase the number of moles of gas in the balloon (by blowing it up) --> the volume increases.
-Increase the pressure on the gas (by squeezing the balloon) --> the volume decreases.
-Decrease the temperature of the gas (by placing the balloon in a refrigerator) --> the volume decreases.
*A mole is simply a unit of measurement, like a dozen or a pair. In this case, it's a really big number: 6.02x10^23 but we use it the same way. A mole of atoms would be 6.02x10^23 atoms, a mole of people would be 6.02x10^23 people, a mole of eggs would be 6.02x10^23 eggs.