1. Warm Up #3
What will happen to the air temperature near the campfire?

2. Lesson 2 Thermal Energy Transfers
Ch. 13 Thermal Energy
Lesson 2 Thermal Energy Transfers

3. Essential Questions
What is the effect of having a small specific heat?
What happens to a material when it is heated?
In what ways can thermal energy be transferred?

4. Radiation
Radiation – the transfer of thermal energy from one material to another by electromagnetic waves
Warm objects emit more radiation than cold objects

5. Conduction
Conduction – the transfer of thermal energy between materials by the collisions of particles
When kinetic energy is transferred, thermal energy is transferred
Continues until thermal energy of all particles in contact is equal
How is this cold glass of lemonade warmed by warm air?

6. Thermal Conductors and Insulators
Thermal conductor – a material through which thermal energy flows easily
Ex: the buckle (metal part) of a seat belt
Thermal insulator – a material through which thermal energy does not flow easily
Ex: the cloth that makes up the seat belt
Why are cooking pots and pans usually made of metals?

7. Specific Heat
Specific heat – the amount of thermal energy required to increase the temperature of 1 kg of a material by 1°C
Low specific heat = less energy to change temperature
(thermal conductors)
High specific heat = more energy to change temperature
(thermal insulators)

8. Thermal Expansion and Contraction
Thermal contraction – decrease in a material’s volume
when its temperature decreases
Thermal expansion – an increase in a material’s volume
when its temperature increases

9. Convection
Convection – the transfer of thermal energy by the movement of particles from one part of a material to another
Only occurs in fluids
Will continue until everything is the same
temperature
Convection current – movement of fluid in a
cycle because of convection

10. Creating Convection Currents ACTIVITY
Place beaker of water on a hot plate
Add a drop or 2 of cold food coloring
What do you notice happening?