Physics Chapter 21 Notes Temperature, Heat, & Expansion

• Chapter 21 Terms & Objectives
• Concepts (PowerPoint presentation)
• Temperature - related to average KE of molecules
• Fahrenheit scale
• Celsius scale
• Kelvin scale
• Internal Energy - total KE and PE of molecules
• Heat - transfer of internal energy due to a temperature difference
• compare to Work - transfer of energy due to a force
• If there is thermal contact, heat "flows" from high temperature to low temperature until thermal equilibrium is reached.
• 1 calorie = heat to raise temperature of 1 gram of water by 1o Celsius = 4.2 Joules
• 1 Calorie = 1000 cal (diet calorie)
• Specific Heat Capacity
• amount of energy need to raise the temperature of 1 gram of a substance by 1oC
• high specific heat capacity
• lots of energy required to raise the temperature
• lots of energy available at high temperature
• Water's specific heat capacity is high (1 cal/gramoC)
• low specific heat capacity
• large rise in temperature for a little added energy
• not much heat energy available even at high temperatures
• Solving heat transfer problems
• • Example
• Expansion
• most substances expand when heated
• solids least, gasses most
• water's behavior is unusual
• maximum density at 4oC
• pond freezing
• Lab & Demos:
• Demo: Expansion of Gasses, Liquids, and Solids