Glossary
Area
The extent or measurement of a surface, used in the calculation of pressure as the surface over which a force is distributed.
Example:
A sharp knife cuts easily because the applied force is concentrated over a very small area, resulting in high pressure.
Atomic Collisions
The frequent impacts of gas atoms or molecules with each other and with the container walls, which are responsible for gas pressure and energy transfer.
Example:
In a sealed bottle of soda, the fizz is due to carbon dioxide molecules undergoing constant atomic collisions with the bottle's interior, creating internal pressure.
Average Kinetic Energy
The mean translational kinetic energy of the particles in a gas, which is directly proportional to the absolute temperature of the gas.
Example:
If you heat a gas, its average kinetic energy increases, causing the particles to move faster and collide more vigorously with container walls.
Force
An interaction that, when unopposed, will change the motion of an object; in gases, it's the sum of impulses from particle collisions on a surface.
Example:
The force exerted by the air inside a basketball pushes outwards, giving the ball its shape and bounce.
Kinetic Theory of Gases
A model that explains the macroscopic properties of gases, such as pressure and temperature, by considering the microscopic motion and interactions of their constituent atoms or molecules.
Example:
The Kinetic Theory of Gases helps us understand why a balloon expands when heated, as the gas particles move faster and collide more forcefully with the inner walls.
Momentum Conservation
A fundamental principle stating that the total momentum of an isolated system remains constant, often applied to analyze the interactions during atomic collisions.
Example:
When a gas molecule bounces off a container wall, its change in momentum is equal and opposite to the impulse exerted by the wall, illustrating momentum conservation.
Pressure
The force exerted perpendicularly per unit area by gas particles colliding with the walls of their container.
Example:
When you inflate a car tire, the air inside exerts pressure on the rubber, keeping the tire firm and supporting the vehicle's weight.
Temperature
A measure of the average kinetic energy of the atoms or molecules within a substance, indicating its degree of hotness or coldness.
Example:
A hot air balloon rises because the air inside has a higher temperature, meaning its molecules have greater average kinetic energy and are less dense.