1. Heat

2. Kinetic-Molecular Theory
All molecules have kinetic energy at all times
Molecules collide with each other randomly and elastically.
Faster molecules will collide with more energy, causing more pressure, and will spread out if possible.

3. Internal energy Temperature
Equal to the total energy of all of its particles
Depends on the size of the sample
Proportional to its temperature
Temperature
Temperature: the average kinetic energy of an object’s molecules
Higher temperature means faster molecules.
Hotter objects will spread out more and expand.
The pressure changes if it cannot spread out.

4. Temperature Scales/Conversions
Units: Kelvin (K) or Degrees Celsius (°C).
Scale Ice point Steam Point
Fahrenheit 32oF 212oF
Celsius 0oC 100oC
Kelvin K K

7. Heat Heat: Energy transfer between objects of different temperature
Heat always flows from higher temperatures to lower temperatures

9. Heat & Energy Loss
When energy is lost from a system, it transforms into Heat.
Examples:
When friction causes a sliding object to slow down or stop, the kinetic energy turns into heat.
When a clay ball is thrown at a wall, the kinetic energy turns into heat that increases the temperature of the clay.
When electrons move through a resistor, the electrical energy turns into heat.
A machine loses efficiency in each process as mechanical energy is lost as heat to the surroundings.
This is the most important slide for the entire unit!!!

10. Thermal Equilibrium
Thermal Equilibrium: No thermal energy transfers between objects in contact.
No heat transfer
Objects have the same average kinetic energy (same Temperature)
Hotter objects will transfer heat to cooler objects until the objects reach thermal equilibrium.

11. Thermal Expansion
When an object’s temperature increases, it will expand.
Metals expand more than other solids.