1. Thermal Energy & Heat
Heat and Its Uses

2. THERMAL ENERGY & MATTER Think About this…
In which direction does heat flow spontaneously?
Define TEMPERATURE
How is THERMAL ENERGY transferred?
What are the factors that determine the THERMAL ENERGY of a material?
Which type of material heats more, one with a high specific heat, or one with a low specific heat?
Is WORK 100% efficient? How do you know?

3. THERMAL ENERGY & MATTER
Work and Heat- work is never 100% efficient. Some is always lost to heat.

4. THERMAL ENERGY & MATTER
Heat- the transfer of thermal energy from one object to another because of a temperature difference.
In what direction does heat flow spontaneously?
FROM HOT to COLD

5. THERMAL ENERGY & MATTER
Temperature = measure of how hot or cold something is compared to a reference point.
Temperature is the average kinetic energy of the particles in an object.
In the image below, where is average kinetic energy greater?
Higher temperature 

6. THERMAL ENERGY & MATTER
Heat flows DOWN the bar through COLLISIONS.
Collisions transfer thermal energy from hot to cold.

7. THERMAL ENERGY & MATTER
Thermal energy- total potential and kinetic energy in an object. It depends on mass, temperature, and phase of an object.
If both objects are in the same phase & at the same temperature, which one has MORE thermal energy?
Because there
are MORE
particles moving
around.

8. THERMAL ENERGY & MATTER
Thermal expansion/contraction - change in volume of a material due to temperature change.
Occurs because particles of matter collide more or less as temperature changes.
Thermal expansion 
Also, wrap on beaker and lava lamp

9. THERMAL ENERGY & MATTER
Specific Heat – amount of heat needed to raise ONE gram of a material ONE degree Celsius.

10. THERMAL ENERGY & MATTER
The LOWER a material’s specific heat the MORE its temperature rises when energy is added.
Which will heat faster (has the lower specific heat)?
Water? Or Lead?
YES!
Specific heat of water = 4.18 J/g°C Specific heat of lead = 0.46J/g°C

12. The transfer of thermal energy with no transfer of matter.
HEAT TRANSFER
What type of HEAT TRANSFER is occurring in the pictures? Conduction, convection or radiation?
CONDUCTION –
The transfer of thermal energy with no transfer of matter.

13. HEAT TRANSFER
What type of HEAT TRANSFER is occurring in the pictures? Conduction, convection or radiation?
CONVECTION –
The transfer of thermal energy when particles of a liquid or gas move from one place to another

14. HEAT TRANSFER
CONVECTION – in the earth and sun

15. HEAT TRANSFER
What type of HEAT TRANSFER is occurring in the pictures? Conduction, convection or radiation?
RADIATION –
The transfer of thermal energy by waves moving through space. ALL OBJECTS radiate energy!

16. THERMODYNAMICS
The study of conversions between thermal energy and other forms of energy.

17. THERMODYNAMICS
First Law: Energy is Conserved

19. THERMAL ENERGY & MATTER Think about this…
Define Convection, Conduction and Radiation
Give an example of each.
Write a sentence describing how each is important to our everyday lives.
How do we use heat in our everyday lives?

20. Temperature Scales Three different ones get used
Fahrenheit- the one we use
Celsius- metric standard
Kelvin- starts at absolute zero but same degree size as Celsius

21. Converting Temperature
F = 9 C
K = C + 273
Water freezes at 32°F, what is this in Celsius?
In Kevin?
Water boils at 100°C. What is this in Fahrenheit?
In Kelvin?

22. 100⁰C
212⁰F
373 K
0⁰C
32⁰F
273 K
-273⁰C
-492⁰F
0 K

23. Conversion Practice
Body temperature is 98.6°F, what is this in Celsius? In Kelvin?
Methanol boils at 75°C, what is this in Fahrenheit?, in Kelvin?
Lead melts at 600 K, what is this in Celsius? In Fahrenheit?