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Apr. 14, 2011

Harnessing the Elements: Energy Transfer

by Christopher Hong

OBJECTIVE
Students will be able to:

1) understand energy and give examples of energy
2) distinguish between potential and kinetic energy
3) understand that energy does not get created nor destroyed, but rather it is transferred or converted from one thing to another

KEY CONCEPTS AND VOCABULARY
Energy – the ability to push an object from one place to another; ability to do something
Potential Energy – height energy; it can do something later
Kinetic Energy – movement energy
Energy Transfer – energy moves from one object to another usually through contact

CONNECTION TO THE STORY
This is the first of four lessons about controlling the elements. Why is it beneficial to harness the elements? Because the supply of nonrenewable energy (fossil fuels) in this world is decreasing and will eventually run out. Thus, we will eventually need to use another form of energy -- such as wind or solar energy -- that is renewable and can provide a continuous supply. Before we talk about renewable energy, we must understand energy, along with the two main types of energy –- potential and kinetic. It is also important to understand that energy cannot be created or destroyed but can only be passed on from one thing to another, usually through contact.

MATERIALS
1 for each group:
• Pipe Insulator
• Ping Pong Ball
• Cup
• Roll of tape
• Pencils/pens
• Plastic spoon
• Plastic fork
• Paper plates

Extras to share:
• Paper
• Tissues
• Marbles
• Staples
• Blocks
• Crayons
• Cardboard
• String

For demos:
• Flexible ruler (to make catipult)
• Ball
• Book

DEMONSTRATIONS

DEMO 1 – OK GO
Watch the amazing video:
Video by OKGO

Some discussion questions:
Q: Does anyone know what an engineer does?
A: In short, engineers are people who design solutions to problems. Engineers built that contraption in the video.

DEMO 2: Energy
Tell everyone to push an object on the table

Q: What is energy?
Q: Have you been told that you were energetic before? Why did someone tell you that you were energetic?

A: Energy is the ability to push an object from one place to another or to put it simply – to do something. When you wake up in the morning, it takes energy to get up. It takes energy for you to walk and write. So, an object has energy if it can push something from here to there. For example, I have energy to push this table across the room.

Q: Can you think of other things that have energy? Do moving things have energy? If they bump into something, will that object move?

DEMO 3: Kinetic Energy

Throw a ball across the room.

There are two main types of energy. The first one is kinetic energy. Kinetic energy is movement energy. When something is moving, it has kinetic energy.

Q: What kind of energy does this ball have as its flying in the air?

DEMO 4: Potential Energy
The other type of energy is potential energy. Potential energy is when an object has the ability to do something later. One example of potential energy is height energy. When you lift a book and put it on the shelf, you need to spend energy to put it on the shelf. Therefore, the book has potential energy because in the future, if it falls, it can do something such as move another object.

Pick up book; drop it on an object to move it.

Ask everyone to put their pencil on the floor then lift it up to their chest. Then ask everyone to try to lift their chair to their chest. What is the difference? Which one is harder? Did you spend more energy doing one or the other? The heavier an object is, the more energy it is required to lift up and thus the more potential energy it has.

DEMO 5: Catapult
Demonstrate a simple catapult (you can build one with a flexible ruler and an object like a ping pong ball.)

Energy in this world is neither created nor destroyed. It is just converted to other forms and transferred from one object to another. For example, I pushed this table. My energy is being passed on to the table. I throw this ball, I pass on energy to the ball. This is energy transfer.

Q: What happens when the catapult flings the ball? Think about energy? Try not to use the word energy.
The demonstrator's energy was passed on to the ruler, and the ruler’s energy was then passed on to the ball.

DEMO 6: Dominoes
Another example of energy transfer is dominoes.

Video by timcaspar

HANDS-ON ACTIVITY

A Rube Goldberg machine is what you saw in the first video -- a deliberately over-engineered machine that uses a complex chain reaction to perform a very simple task. Ask the students to use the materials provided to build a Rube Goldberg machine that will push a ping pong ball into a cup. Ask them to design their contraptions with at least 5 different transfers of energy. For example, the machine should not just have five blocks pushing each other down, but should have lots of different kinds of energy transfers. Students have the freedom to make whatever they want, but they should continually test that the contraption works.

REFLECTION
At the end, ask everyone to show off their Rube Goldberg machine and explain how the energy is being transferred (i.e. the marble transferred energy by pushing the block down a ramp so now the block has energy).

ASSESSMENT
Q: What is energy?
Q: Give some examples of things with kinetic energy.
Q: Give some examples of things with potential energy.
Q: Give some examples of energy transfer.

Read a teacher's personal account of using this lesson plan at Rube Goldberg Machines and Energy Transfer.

__________
Christopher Hong is a sophomore electrical engineering student at The Cooper Union.

Iridescent, a science & engineering education nonprofit, uses science, engineering and technology to develop persistent curiosity and to show that knowledge is empowering. Through their Engineers as Teachers program, Iridescent trains undergraduate, graduate and professional engineers and scientists to develop engaging, hands-on, design-based science courses for underserved children and their families, and to communicate cutting-edge science concepts to large, diverse, public audiences.

 

About Christopher Hong

The views expressed are those of the author and are not necessarily those of Science Friday.

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