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.

1 comment:

  1. Thank you so much for this. This is a very good explanation. I am in high school right now and I needed a picture showing how the Ideal Gas Law worked and this is perfect. Thank you again!
    Good wishes for you and your family.