Heat and Temperature

Temperature and Heat

Temperature and energy

• Temperature is proportional to the average kinetic energy

• Thermal energy is the sum of kinetic and potential energies

• Temperature differences cause energy flow

Open Ended

Describe the difference between temperature and thermal energy.

Equilibrium

• Objects are in equilibrium when the total net energy transfer is 0

• zeroth law

• -objects in contact with one another are in thermal equilibrium if they have the same temperature. nothing else matters

Open Ended

Do objects contain "heat". explain your reasoning.

Heat

• Heat should be considered as the "transfer of thermal energy".

Measuring Temperature

• Celsius= 5/9 ( Fahrenheit temp - 32)

• Fahrenheit= 9/5 (celsius) + 32

• Kelvin= C + 273.15

• Kelvin is based on absolute zero- the point at which an object cannot be further cooled

Multiple Choice

Convert 68 F to celsius.

Convert -2 C to Fahrenheit

• 20 C, 16 F

• 16 C, 20 F

• 20 C, 28 F

Thermal Expansion

• An increase in temperature normally causes expansion

• There is a coefficient of themal expansion-  $\alpha$  

•  $\Delta L=\alpha L_i\Delta T$  

Fill in the Blanks

Th eiffel tower is made of iron. If the tower is 301 m high on a day when the temperature is 22 C, how much does its height decrease when the temperature cools to 0.0 C? coefficient of thermal expansion is 12x10^-6 K^-1.

Open Ended

Research a situation where thermal expansion is beneficial.