13+Measuring+Heat

=**__Measuring Heat__**=

**Units of Heat**

 * The basic unit of heat is the **calorie**. One calorie is equal to the amount of heat that is required to heat one gram of water one degree celsius.
 * Another common unit of heat is the **British thermal unit**, or **Btu**. One Btu is equal to the amount of heat required to change the temperature of one lb of water by one degree Fahrenheit.
 * The unit used for labeling food is the **Calorie**. One calorie is equal to one thousand calories.
 * The SI unit of heat is the **joule**. One joule is equal to 4.184 calories.

**Specific Heat Capacity**

 * **Specific Heat Capacity** is the amount of heat energy required to change the temperature of a unit mass of a substance by one degree.
 * Every substance has a different specific heat capacity.
 * The unit for specific heat capacity is cal/g°C.

**Heat Equation**

 * Heat=Mass*Specific Heat Capacity*Temperature Change
 * In variables: Q=mcΔT
 * In units: cal=grams*cal/g°C*°C

**Thermal Expansion**

 * When the temperature of a substance is increased the molecules move faster and become farther apart causing the object to expand.
 * Almost all substances- solids, liquids, gases, and plasmas expand when heated and contract when cooled.
 * Water is an exception because when heat is added to melt ice, the water contracts until it reaches 4 degrees.