# What is Temperature?

Temperature is the average speed (V) or the kinetic energy of the atoms for molecules in a substance.

There are three different temperature scales:

• Celsius
• Fahrenheit
• Kelvin

• Absolute Zero is the lowest temperature possible. It is the temperature at which all molecular motion/energy stops. This is from the Third Law of Thermodynamics, we will talk about the First Law later.
• The lowest temperatures observed are in the depths of outer space, these temperatures are 3 degrees above absolute zero.
 Temperature: Fahrenheit Celsius Kelvin Of Absolute Zero -459 -273 0 which water freezes 32 0 273 which water boils 212 100 373

As you can see Celsius and Kelvin are on the same scale, 273 degrees apart:
C = K - 273

The converson between Fahrenheit and Celsius is alittle more complex:
C = (F-32)*(5/9) or F = (9/5)C + 32

## What is heat?

Heat is the total internal kinetic enery of the atoms and molecules that make up a substance. Since heat is a form of energy, it is measured in Joules.
• 1 Joule = 1 Nm = 1 kg m2/s2
• 1 calorie is the heat energy needed to raise 1 gram of water by 1 degree Celsius. 1 calorie = 4.186 Joules

Two liters of boiling water has more heat (energy) that one liter of boiling water.
Heat will not flow between two objects of the same temperature.
Heat is really energy in the process of being transferred from one object to another because of the temperature difference between them.