1. Temperature and Pressure

2. Temperature  a measure of the average kinetic energy (motion) of the particles in an object; how fast the particles are moving.  The faster they are moving, the higher the temperature.  The slower they are moving, the colder the temperature.  Always goes from hot to cold.  Stops at thermal equilibrium.

3. Three Temperature Scales  We use three scales to measure temperature.  Fahrenheit  Celsius  Kelvin

4. Fahrenheit (°F)  Used in the USA  Based on the lowest temperature that Dr. Fahrenheit could achieve (mixture of ice, salt, and alcohol)  180 degrees between freezing and boiling points of water

5. Celsius scale: (°C)  Created by Anders Celsius  Also called the centigrade scale  Based on freezing/boiling points of water  Used by most of the world and by scientists  Considered by some to be an SI unit  100 degrees between freezing/boiling points of water

6. Kelvin scale: (K)  Kelvins, not degrees Kelvin  Based on absolute zero, the coldest possible temperature. This is the point where all the motion of the particles has stopped. Believed to be impossible to achieve.  Has no negative numbers  Official SI unit  Same size as Celsius degrees, just starts at a different place  Used by scientists only

8. Pressure

9. Pressure (SI)  Is the force (a push or a pull) applied over an area.  If we apply 1-Newton of force over 1-meter 2 we have the SI unit for pressure, the Pascal.  Since this is a very small amount of force, we will typically measure pressure in kilo-Pascal's, or (kPa).  You might find this unit on your bicycle tire.

10. Pressure (customary)  In America we measure force in pounds and area in inches 2, so we measure pressure in pounds per square inch.  This unit is abbreviated psi.  You will see this on your bicycle tire.

11. Pressure Formula  Pressure = force/area  If we increase force, the pressure goes up.  If we decrease the force, the pressure goes down.  These are called directly proportional relationships.

12. Inverse Relations  Pressure = force/area  If we increase the area, the pressure will decrease.  If we decrease the area, the pressure will increase.  We call this an inverse relationship.