Heat Transfer Vocabulary 8. Temperature Temperature is the average amount of energy in a substance. 9. Thermal energy Thermal Energy is the total amount of energy. 10. Thermometer Is used to measure air temperature.  A thermometer is a glass tube with either mercury or alcohol inside.  It works because the liquid inside expands when the air temperature goes up. 11. Heat The transfer of thermal energy from a hotter object to a cooler one because of difference in temperature.  There are three ways heat can be transferred. 12. Conduction The direct transfer of heat from one substance to another that is touching.  The closer the molecules together the better they are at conducting heat.  Conduction works well in solids (many metals) but not as well in liquids or gases.  Air and water are not good conductors of heat. 13. Convection The transfer of heat by movement (changes in temperature) in liquids and gases is called convection. 14. Convection Currents The movement of air due to changes in temperature.  Heat makes particles move further apart becoming less dense. This less dense air rises, until it is cooled in the upper atmosphere where it then falls.  This creates an air current. 15. Formula to convert from Fahrenheit to Celsius 16. Formula to convert from Celsius to Fahrenheit 17. Freezing Point of Water in both Fahrenheit and Celsius Freezing Point a.       In Fahrenheit is 32ºF b.      In Celsius is 0ºC 18. Boiling Point of Water in both Fahrenheit and Celsius Boiling Point a.       In Fahrenheit is 212ºF b.      In Celsius is 100ºC