A model of gas.
Before studying gases in depth. You need to have a model (picture) of what a gas looks like
Lets imagine a container filled a gas. The molecules in the gas are identical. In our model we see lots of tiny indentical balls moving around randonly. Balls will be hitting the sides of the container and constantly bumping into each other. Each collision (either with the container or other balls) is elastic. This means that there is no loss of kinetic energy when a collision happens.
Volume, Pressure and Temperature in our model
Volume: This is just the amount of space taken up by the gas. This is always equal to the
amount of space taken up by the container. Remember a gas will always fill the container it is in. In our model,
those little balls are free to move anywhere within the container.
Pressure: This is the amount of force per square metre on the sides of the containers. In our model, this
is equivalent to average force (per square metre) of the balls colliding with the sides of the container
Temperature: This is a measure of the average kinetic energy of the molecules within the gas. In our model
this is the average kinetic energy of the balls. Remember, in our model, the balls are moving randomly, so each molecule will
have have a different amount of kinetic energy