1. Warm up: In your composition book.
In your own words, describe Heat.
In your own words, define temperature.

2. Temperature and Heat We are starting a new chapter
Title today’s notes:
Temperature and Heat

3. Thermal Energy:
All matter is made of particles
These particles are always bouncing around.
These particles have kinetic energy and potential energy.
Thermal energy is the total amount of potential and kinetic energy contained in the particles that make up a substance.

4. Plickers link

5. Temperature
Temperature is a measure of the average kinetic energy of all the particles in an object.
tells how hot or cold something is
Higher KE=Higher temperature
Lower KE=Lower temp

6. Plickers link

7. Boiling Water in a Paper Cup
Heat
Heat is the movement of thermal energy from warm objects to cooler objects.
Thermal energy always flows to the objet with lower temp until thermal Equilibrium is reached.
Thermal Equilibrium occurs when all objects have reached the same temperature.
Boiling Water in a Paper Cup

8. Plickers link

9. Specific Heat Different substances heat up more easily than others.
Specific heat: The amount of thermal energy needed to raise the temperature of 1kilogram of a material 1°C
Different substances heat up more easily than others.
Look at pg. 325 Table 1
What object has the highest specific heat?
What object has the lowest specific heat?
Which object is the easiest to warm up?

10. Table of Specific Heat Values
Substance
Specific Heat
(cal/g0C)
(J/kg0C)
Air
0.25
1,046
Aluminum
0.22
899
Copper
0.09
387
Glass
0.20
837
Ice (-200C to 00C)
0.50
2,090
Iron
0.11
448
Mercury
0.03
138
Ocean Water
0.93
3,894
Water
1.00
4,187
Wood
0.42
1760

11. Look at formula on page 326
Write down formula in your notes

12. Calculating changes in thermal energy
Change in thermal energy=(Mass)(Temperature change)(Specfic Heat)
Formula:
Q=(m)(ΔT)(C)
What does Q stand for?
What does ΔT stand for?
What does C stand for?

13. Copy down this Practice problem
The air in a room has a mass of 50 kg and a specific heat of 1,000J/(Kg°C). What is the change in thermal energy of the room when it warms from 20°C to 30°C?

14. Calculating thermal energy changes
Thermal energy equation.
(mass)(Tempfinal-Tempinitial)(specific heat)=Change in thermal energy
Q=m(Tf-Ti)C
Assignement. Complete problems 1-10 on page 142,143

15. Warm up 11/16/15
An equal mass of water and rubbing alcohol are heated at the same rate for 10minutes. At the end 10 minutes the alcohol has a higher temperature. Which one has the higher specific heat?

16. Specific Heat Capacity
the amount of energy needed to change the temperature of 1 kg of a substance by 10C
how easily substances change temperatures
Water has a very high specific heat capacity
the higher the speciific heat  the more energy and the longer it takes for something to heat up and cool down. to heat up or cool down
can be used to help calculate heat lost or gained by a substance
formula: mc∆T

17. Using Specific heat to calculate change in energy.
Water has specific heat of 4200J/(kg°C) Using this value we can calculate how much energy was transferred by each type of material in our lab. -Change in thermal energy=(mass)(Temperature change)(specific heat) IF we calculate how much thermal energy was added to the water when dropped our object into the water, we can figure out how much energy the object had.

18. Example Q=Change in thermal energy Mass=Mass of water in foam cup
Temperature change= Temp after object is dropped in-Temp before object is dropped in
specific heat=4200
Q=(m)(Tempbefore-Tempafter)(C)

19. Example You had 100mL water which =0.1kg If temp went from 17-21,
tempfinal-timepinitial=21-17=4
Specific heat of water of 4200J/Kgc
Q=(0.1kg)(4)(4200)=1680J was added to the water by the nut.

20. Thermal Energy vs. Temperature vs. Heat
the total energy of the particles in a substance
a measure the average kinetic energy of all the particles in an object
the transfer of energy between objects that are at different temperatures
expressed in joules
expressed in degrees Fahrenheit, Celsius, or Kelvin
expressed in joules or calories
varies with the mass and temperature of a substance
does not vary with the mass of a substance
varies with the mass, specific heat capacity, and temperature change of a substance

21. Conduction
transfer of thermal energy through a substance, or from one substance to another by direct contact of particles
takes place in solids, liquids, and gases, but takes place best in solids because the particles of a solid are in direct contact with each other
Unfortunately for someone, after being touched, the heat will transfer from the iron to the hand. What are some other real-life examples where heat is transferred by conduction?

22. Conductors and Insulators
substances that conduct thermal energy well
particles are close together
different metals are common conductors
Insulators
substances that do not conduct thermal energy well  they delay heat transfer
particles are far apart
different plastics are common insulators
What are some common conductors and insulators?
Melting Blocks

23. Convection
transfer of thermal energy through fluids (liquids or gases) by means of up and down movements called convection currents
the circular motion of liquids or gases due to density differences that result from temperature differences
As the air gets heated by the flame, the particles move faster and spread out. This increases the volume of the air inside the balloon, which lowers the density. This decrease in density causes the balloon to rise.
Sea and land breezes result from uneven heating of the Earth’s surface and the resulting convection currents. Explain how this happens.

24. Radiation
transfer of thermal (radiant) energy as electromagnetic waves, such as visible light or infrared waves
energy can be transferred through matter or empty space
darker objects absorb more radiant energy than lighter objects
Notice how the visible light from the sun travels through space and heats the Earth.

25. Calculating Heat – Sample Problem
How many joules are needed to raise the temperature of 100 kilograms of copper from 10 C to 100 C? The specific heat of copper is 387 J/kg·C.
Take the
difference
between 100C
and 1000C
Q = mc∆T
heat
mass
specific
heat
change in
temperature
Heat =
(100 kg)
387 J
kg·C
(90 C)
Heat = 3,483,000 J