1. Unit 3: Energy

2. Types of Energy Moving Potential for Motion Kinetic Energy
________________________
Thermal Energy
Sound Energy
Electrical Energy
Gravitational Potential Kinetic Energy
________________________
Elastic Potential Kinetic Energy
Chemical Energy
Nuclear Energy
Light Energy
- _________________________

3. Motion – Kinetic Energy
Motion of objects larger than molecules
Typically motion of objects we can see with the naked eye

4. Motion – Thermal Energy
The average motion of all the particles in an object
Particle means atoms and/or molecules and/or proton/neutrons in this case

5. Motion – Sound Energy
A wave of particles (usually encountered as air for us humans) hitting their nearest neighbors, transferring their energy

6. Motion – Electrical Energy
The motion of electrons through a medium, usually metal
What other things can electricity travel through?
water
air
and more!

7. Potential – Gravitational Potential Kinetic Energy
A macroscopic object could move faster because gravity is pulling on it.

8. Potential – Elastic Potential Kinetic Energy
An object could move faster because there is either attraction or repulsion acting on it.

9. Potential – Chemical Energy
Energy is trapped in the chemical bonds between atoms in a molecule.
Most molecules, when given a little push to break apart, separate and move very quickly.
What is that fast atomic motion known as?

10. Potential – Nuclear Potential Energy
Instead of energy trapped in the chemical bonds between atoms, this is the energy trapped in the atom’s nucleus itself
Requires a much bigger “push” to break apart, but the particles will move VERY fast if they are separated
What is this motion known as?

11. Transfer of Energy – Light Energy
Light is the succession of a magnetic field and electric field. Each one creates another field a little further out
Known as electromagnetic radiation for a reason!
Light comes from the motion of electrons, creating an electric field

12. Transfer of Energy – Light Energy cont.
What was thermal energy again?
Atoms moving around
When an atom moves, so does its electrons
Recall: moving electrons create light

13. Transfer of Energy – Light Energy cont.
It is a transfer of energy because light is not made of matter
Light is like potential energy because it can make things (like electrons) move
Light is like kinetic energy because it itself, moves
It’s moving potential energy… so it’s a bit of both

14. (4 min) To your partners:
Where does light come from?
What can it move?
Why is it like both Kinetic and Potential Energy?

15. Solar powered airplane
“The Solar Impulse”
Solar powered airplane

16. Background: Powered by solar panels exclusively.
Can fly 24 hrs a day, 7 days a week.
Some excess energy is stored in batteries onboard the plane.
Batteries can NOT hold enough energy to power the plane through the night.

17. Question:
How is it that The Solar Impulse can fly through the night if its batteries don’t store enough energy to power it’s engines through the whole night?

18. Think about:
Water and Light Energy

19. Which got hotter?
12:48 PM
2:24 PM

20. Over the course of 94 minutes, which type of water gained the most thermal energy?
Clear Water
Algae water
No difference between the two types

21. What factors would affect the temperature?
Based on how liquid uses the Light Energy.
Based on mass of particles.

22. Possibility 1 Based on usage of Light Energy:
Light converted to thermal energy
Added thermal energy
Light used for photosynthesis
Subtracted thermal energy

23. Absorbing Light: What water absorbs more light?
What’s the assumption here?
All light used for photosynthesis.

24. Possibility 2 Based on mass of particles:
Temperature = average speed of particles.
2 objects with same energy could have diff speeds based on their mass
Speed is temp, mass could be size of particles

25. Mass of particles: Which particles go faster when hit with same # energy?
What’s the assumption here?
Algae’s speed will be increased more than H2O.

26. Let’s find out!

27. Data

28. Over the course of 94 minutes, which type of water gained the most thermal energy?
Clear Water
Algae water
No difference between the two types

29. Thinking about Graphs: What could explain this decrease in temperature?

30. Conservation of Energy
What does it mean for real life?
Conservation of Energy

31. 1. You made a hot pot of pasta
1. You made a hot pot of pasta. Which situation heats up your kitchen more?
Letting pasta cool off on the counter
Putting pasta in the refrigerator
They are the same ?

32. Can’t use energy to “delete” energy.
Refrigerator actually removes the thermal energy of the air inside, transfers it to the area around the refrigerator.
T.E.

33. 1. You made a hot pot of pasta
1. You made a hot pot of pasta. Which situation heats up your kitchen more?
Letting pasta cool off on the counter
Putting pasta in the refrigerator
They are the same

34. 2 Reasons for warmer w/ fridge
Counter
Fridge
Left on counter will reach equilibrium temp slightly above current room temp (some energy stays in pot).
No energy in or out of system.
Left in fridge, T.E. in pot will be forced out into the kitchen (less energy in pot, more in kitchen).
Some energy into the system (electrical energy to fridge  T.E.)

35. (3 min) Summarize to and question your table group!
Hot Pasta Pot Left…
On counter
In refrigerator
E.E.
E.E.
(3 min) Summarize to and question your table group!

36. 2. Which of these statements is most compatible with Conservation of Energy?
Sunlight hits leaves on a tree and some of the light energy is absorbed by the leaves, making the shade cooler
A refrigerator uses electric energy to reduce the thermal energy of the air inside of it

37. 3. An example that outlines Conservation of Energy is:
A car converts some of the energy trapped inside gasoline to kinetic energy to move, and sound energy
An animal converts some of the energy in its food into kinetic energy to move, thermal energy to stay warm
A book is dropped, converting gravitational potential energy to kinetic energy to move, and then thermal and sound energy when it hits the ground
A reaction between carbon and oxygen (known as fire), burns a piece of wood, converting the chemical energy into light energy, thermal energy, and sound energy

38. Energy Types, Conservation of Energy, and Green Energy Harvesting
Review

39. Units of Energy Joule BTU kWh (1,000 Watt-hours)
SI unit, standard across planet
BTU
British Thermal Unit (Britain uses it)
kWh (1,000 Watt-hours)
kiloWatt-hour (measures electricity consumed multiplied by time used)
used by American power companies

40. Units of Energy (cont.) calorie Calorie
1 calorie is required to increase 1mL of water by 1 ℃
Calorie
1,000 calories. Also known as a kilocalorie
Used to measure energy in food

41. 4. If a car’s engine has an efficiency rating of 20%, and it consumes 100J of energy, how much energy was transferred into motion of the car?
20J
80J
120J 2J
𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦= 𝑢𝑠𝑒𝑓𝑢𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑐𝑜𝑛𝑠𝑢𝑚𝑒𝑑 𝑒𝑛𝑒𝑟𝑔𝑦 100

42. 5. The term vampire appliance commonly refers to:
Generate more power than they consume
Consume electricity even when they are not operating
Are EnergyStar rated
Are programmed to turn themselves off at midnight each night

43. 6. “Radiant Energy” oftentimes refers to:
Light Energy
Kinetic Energy
Chemical Energy
Nuclear Energy

44. 7. Hydroelectric power DIRECTLY harvests _________ energy.
Kinetic
Gravitational Potential
Light
Chemical

45. 8. Hydroelectric power INdirectly harvests _________ energy.
Kinetic
Gravitational Potential
Light
Chemical

46. 9. Ultimately, the energy necessary for hydroelectric power is:
Light/Radiant energy
Kinetic Energy
Gravitational Potential Energy
Chemical Energy
Electrical Energy

47. 10. Which of the following forms of energy harvesting is most efficient?
Sunlight through a window warming up a room.
Burning oil to heat water which is pumped through pipes to heat a room.
Using the thermal energy generated by a group of people to heat a room.
Heating a room with electric heat which gets its power from active solar panels on the roof.
Burning coal at a powerplant to produce electricity which then powers electric space heater to warm up the room.