1. Welcome back! Thursday, January 29, 2015 Agenda:
Objective: Thermal Energy; I will discuss thermal energy and compare the different ways to transfer heat.
Agenda:
#throwbackthursday: Question of the Day #28 & 29
Energy Vocabulary Quiz
Heat & Thermal Energy Notes
Homework: Energy Unit Quiz Review

2. #throwbackthursday
Work on #28-29 in your green packet independently.

3. CRT Prep: Life Science #28 L. 8. B. 5 http://www. rpdp
The explanation that diseases are caused by microorganisms is known as the
cell theory.
immune theory.
germ theory.
infection theory.
Standard: Structure of Life – All living things are composed of cells. Cells can range from very simple to very complex and have structures which perform functions for the organism. Cells and cell structures can be damaged or fail because of intrinsic failures or disease.
L.8.B.5- Students know disease can result from defects in body systems or from damage caused by infection. E/S
DOK Level 1
Answer C
The germ theory of disease proposes that microorganisms are the cause of many diseases. Since this theory suggested that diseases can be caused by organisms too small to be seen without a microscope, it was highly controversial when first proposed. Now it is a cornerstone of modern medicine, leading to such important innovations as antibiotics and hygienic practices.

4. CRT Prep: Life Science #29 L. 8. B. 5 http://www. rpdp
Exposure to a weakened or mild form of a pathogen to produce immunity is the basis for using a(n)
vitamin.
interferon.
vaccine.
antibiotic.
Standard: Structure of Life – All living things are composed of cells. Cells can range from very simple to very complex and have structures which perform functions for the organism. Cells and cell structures can be damaged or fail because of intrinsic failures or disease.
L.8.B.5- Students know disease can result from defects in body systems or from damage caused by infection. E/S
DOK Level 1
Answer C
A vaccine is a biological preparation that is administered to provide immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins. The agent stimulates the body's immune system to recognize the agent as foreign, destroy it, and "remember" it, so that the immune system can more easily recognize and destroy any of these “live” microorganisms that it might later encounter.

5. Energy vocabulary quiz

6. Heat & thermal energy

7. Thermal Energy
A. Temperature & Heat
1. Temperature is related to the average kinetic energy of the particles in a substance.

8. 2. SI unit for temp. is the Kelvin
a. K = C (10C = 283K)
b. C = K – 273 (10K = -263C)
3. Thermal Energy – the total of all the kinetic and potential energy of all the particles in a substance.

9. 4. Thermal energy relationships
a. As temperature increases, so does thermal energy (because the kinetic energy of the particles increased).
b. Even if the temperature doesn’t change, the thermal energy in a more massive substance is higher (because it is a total measure of energy).

10. a. The flow of thermal energy from one object to another.
Cup gets cooler while hand gets warmer
5. Heat
a. The flow of thermal energy from one object to another.
b. Heat always flows from warmer to cooler objects.
Ice gets warmer while hand gets cooler

11. Land heats up and cools down faster than water
6. Specific Heat
a. Some things heat up or cool down faster than others.
Land heats up and cools down faster than water

12. b. Specific heat is the amount of heat required to raise the temperature of 1 kg of a material by one degree (C or K).
1) C water = 4184 J / kg C
2) C sand = 664 J / kg C
This is why land heats up quickly during the day and cools quickly at night and why water takes longer.

13. Why does water have such a high specific heat?
water metal
Water molecules form strong bonds with each other; therefore it takes more heat energy to break them. Metals have weak bonds and do not need as much energy to break them.

14. How to calculate changes in thermal energy
Q = m x T x Cp
Q = change in thermal energy
m = mass of substance
T = change in temperature (Tf – Ti)
Cp = specific heat of substance

15. First, mass and temperature of water are measured
c. A calorimeter is used to help measure the specific heat of a substance.
First, mass and temperature of water are measured
Knowing its Q value, its mass, and its T, its Cp can be calculated
Then heated sample is put inside and heat flows into water
This gives the heat lost by the substance
T is measured for water to help get its heat gain

16. Heat transfer

17. Heat Transfer
I Like it Hot!!

18. (Room temperature is about 25 Degrees C)
Question
Q: If a cup of hot chocolate and an ice cube were left on the table in this room what would happen to their Temperature? Why?
A: The cup of hot chocolate will cool until it reaches “room temperature.”
A: The ice cube will melt and then the liquid will warm to “room temperature.”
(Room temperature is about 25 Degrees C)

19. Heat Transfer The cooler air warms up and the mug cools Cooler air
Heat always moves from a warmer place to a cooler place.
So:
Hot objects in a cooler room will cool to room temperature.
Heat Energy
Heated liquid/air
The cooler air warms up and the mug cools
down until both are about equal temperature
Cooler air
The air outside the mug is cooler
than the air inside the mug. So the heated air
moves out of the mug into the cooler air

20. All solids (ice) melt when they gain enough heat energy
Heat Transfer
Heat always moves from a warmer place to a cooler place. So:
Cold objects in a warmer room will heat up to room temperature.
Heat Energy
All solids (ice) melt when they
gain enough heat energy

21. Conduction: Movement through direct contact.
Heat Transfer Methods
Heat moves from one place to another by:
Conduction: Movement through direct contact.
Convection: Circular motion of heated fluid material.
Radiation: Light waves through a space or gas.

22. CONDUCTION:
When you heat a metal strip at one end, the heat travels to the other end.
So it’s no wonder that you can hold metal
over a flame without it burning your hand for
a few seconds, but after that…OUCH!!!
Metal Bar
Watch as the atoms closest to the
flame gain more energy first and
the energy simply spreads out
Heat Energy
It takes a little time, but the Heat
Energy spreads out and the
metal gets “hotter”
As you heat the metal, the atoms vibrate faster, these vibrations make the adjacent atoms vibrate, and so on and so on, the vibrations are passed along the metal and so is the heat.

23. Why Metals heat up so fast?
In addition to atom vibrations, the electrons for metal atoms can “drift”; are free to move around within the metal.
= electron
When the metal is heated, the electrons gain kinetic energy and transfer it throughout the metal.
Heat
Energy
“Insulators”, such as wood and plastic, do not have drifting electrons which is why they do not conduct heat as well as metals.

24. Why does metal feel colder than wood, if they are both at the same temperature?
Metal is a conductor, wood is an insulator. The metal conducts the heat away from your hands, the wood does not conduct the heat away from your hands as well as the metal, so the wood feels warmer than the metal.
The hand holding the metal is losing heat
to the metal so it feels cooler!

25. CONVECTION: Cooler, more dense liquids
= “cool” atom
= “hot” atom
Cooler, more dense liquids
and gases (fluids) sink (move down).
Warmer, less dense liquids and gases (fluids) spread out and rise up.

26. Convection: Movement of Heat in a “circular” motion
That’s why its called a “Convection Current!”
Convection: Movement of Heat in a “circular” motion
How does this work in a liquid?
A “current” is a “steady flow” of a “fluid” (liquid and gas)
Hot water rises
Warms back up again.
Hot water rises back up
Cools at the surface
Cooler water sinks
Heat source
Demo: Oil & Thyme

27. Where is the freezer compartment put in a fridge?
Cold air sinks
Where is the freezer compartment put in a fridge?
Freezer compartment
It is warmer at the bottom, so this warmer air rises and a “convection current” begins.
It is put at the top, because cool air sinks, so it cools the food on the way down.

28. Why is it windy at the seaside?
So it moves sideways towards the shore and we feel this motion as a breeze
When the cool air reaches the surface of the water, there is nowhere else for it to go
And we get convection currents of air!
As the cool breeze reaches the land, it heats up, and rises as well!

29. The third method of heat transfer:
How does heat energy get from the Sun to the Earth?
There are no atomic particles between the Sun and the Earth so it CANNOT travel by conduction or by convection. ?
RADIATION=The transfer of heat by electro-magnetic waves!
Also Known as “Light!”

30. Radiation helps keep our planet warm
But some of it escapes back out into
Space = planet doesn’t warm up too much!
Notice that some of the heat gets “trapped” by
the atmosphere and stays here = planet stays warm!

31. There is a lot of energy in Solar Radiation:
After the atomic bomb in Japan. There was
once a large city where this photo is looking.
Now it is completely destroyed!!!
(it only took about 1 second!!!)
Much of this destruction was caused by
radiation
Sunburns are because of
Radiation impacting our skin
There was so much Radiation energy
when the bomb blew up that some people
were simply vaporized!!! YIKES!!!

32. Human Uses for Radiation:
There are some great uses for Radiation;
You can also use radiation to get warm on a camping trip! Or to cook food with a microwave: