Download Energy Conversions - Middle School Chaos Mrs. Piper, Mr. Hysell

Energy Conversions
Answer Key
Vocabulary: chemical energy, electrical current, energy, fossil fuel, global warming,
gravitational potential energy, hydroelectricity, kinetic energy, light, nonrenewable resource,
nuclear energy, renewable resource, sound, thermal energy
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
[Note: The purpose of these questions is to activate prior knowledge and get students thinking.
Students are not expected to know the answers to the Prior Knowledge Questions.]
1. What are sources of electricity? List as many as you can.
Answers will vary. [In the US, major energy sources include fossil fuels, nuclear power,
hydroelectricity, ethanol, wind power, solar power, and geothermal energy Students might
also mention batteries.]
2. Where do people and other animals get energy to move around?
Answers will vary. [People get energy from food.]
3.
Where do plants get energy to live and grow?
Answers will vary. [Plants get energy from the Sun]
Gizmo Warm-up
In the Energy Conversions Gizmo™, be sure Information
mode is selected. Click on each of the different items in the
scene and read about each one.
1. Which object converts sunlight into sugars?
The corn plant
2. Which object converts wind power to electricity?
Wind turbine
3. Which object converts light to electricity? Solar cell
4. Which object converts electricity to light? Light
Activity A:
Energy Paths
Get the Gizmo ready:
 Select the Path mode.
Question: Where do we get energy to run, climb, play, and do all the other things we do?
1. Form hypothesis: Where do you think we humans get energy?
Hypotheses will vary. [Humans get energy from the food we eat.]
2. Create a path: You will now form an energy path to see where our energy comes from.
A. Click on the person and read. Where do people get energy? From food (chicken or
corn)
B. Now click on the chicken. Where does the chicken get energy? From food (corn)
C. Click on the corn. Where does the corn get energy? From the Sun
D. Click on the Sun. How does the Sun get energy? From a nuclear reaction that
converts hydrogen into helium. [The reaction is called nuclear fusion.]
E. Fill in the energy path below starting with the Sun.
Sun → Corn → Chicken → Person
3. Apply: Click Reset and then click on the toaster. Using the Gizmo, create four energy paths
to explain how the toaster could get its energy. (One path will only have three objects.)
A. Sun → Air → Wind turbine → Toaster
B. Sun → Water → Dam → Toaster
C. Sun → Solar cell → Toaster
D. Sun → Corn → Ethanol plant → Toaster
4. Analyze: Where does each path begin? The Sun
5. Draw conclusions: What would life on Earth be like without the Sun?
Answers will vary. [Earth would be very cold and there would be little or no energy on Earth.
Plants wouldn’t grow, wind wouldn’t blow, and water would not evaporate. No clouds would
form and no rain or snow would occur. Living things would not survive.]
Get the Gizmo ready:
Activity B:
 Click Reset.
 Check that Path mode is still selected.
Energy
Conversions
Question: How is energy changed from one form to another?
1. Classify: Energy is the ability to exert force and cause change. Energy exists in many forms:

Kinetic energy is energy of motion. Two examples are given below.
o
Sound is energy of vibrating materials or air molecules.
o
Thermal energy is the energy of tiny moving particles. As an object heats up,
particles move faster and thermal energy increases.

Gravitational potential energy is stored energy that exists based on the position of
an object. The higher an object is, the greater its gravitational potential energy.

Electrical current is energy that comes from moving charged particles.

Light is electromagnetic waves that are visible to the eye.

Chemical energy is energy that is stored in the bonds holding atoms together.

Nuclear energy is energy released when atoms split apart or join together.
2. Create path: Create an energy path in the Gizmo, starting at the Sun. For each step of the
path, describe the energy conversion that takes place. The first one is done for you. Discuss
your answers with your classmates and teacher. Answers will vary. One example is given.
Energy Path
Energy conversion
____Sun_____
Nuclear energy is converted to light and thermal energy.
____ Air_____
Thermal energy is converted to kinetic energy.
_ Wind turbine_
Kinetic energy is converted to electrical current.
____Sound____
Electrical current is converted to sound.
3. On your own: Create at least two more paths on the Gizmo. List the energy conversions that
happen along each path. Record your work on separate paper or in your notebook.
Check student work.
4. Apply: Where in the Gizmo (and in real life) do the following energy conversions occur?
Chemical to thermal to electrical current: Ethanol plant
Gravitational potential to kinetic to electrical current: Dam
Extension:
Renewable Energy
Get the Gizmo ready:
 Click Reset.
 Select the Information mode.
Introduction: Over 80% of our energy comes from the burning of fossil fuels such as oil, gas,
and coal. Fossil fuels are fairly cheap and plentiful, but there are several problems:

Fossil fuels are nonrenewable resources. That means there is a limited supply. Once
the world runs out, there is no way to get more.

Burning fossil fuels adds carbon dioxide to the air. Most scientists agree that this causes
the gradual warming of Earth’s climate, or global warming.
Question: What types of energy do not harm our environment?
1. Describe: Four examples of renewable resources are featured in the Energy Conversions
Gizmo. These resources are produced all the time, so they will not run out. Read about each
energy source, and then explain how each is produced in your own words.
A. Wind power:
The Sun heats up pockets of air*, which rise. Cooler air rushes in, causing wind.
Wind turns the blades of a wind turbine. The blades turn a loop of wire inside a
magnet. This causes an electrical current to flow in the wire.
*[Note: Sunlight is actually absorbed by Earth’s surface, which then radiates heat
and causes the air to warm up.]
B. Water power (also called hydroelectricity):
Falling water turns the blades of a turbine. The blades turn a loop of wire inside a
magnet. This causes an electrical current to flow in the wire.
C. Solar power:
Electrons are removed from silicon crystals by sunlight. The electrons make an
electrical current in the wire.
D. Ethanol:
Corn is fermented to make ethanol. Ethanol is burned, which boils water. The steam
from the boiling water turns a turbine and powers a generator.
2. On your own: Learn more about one of these renewable resources using the internet or by
reading library books. Explain its advantages and disadvantages to your teacher and class.
[This activity is optional but would make for good class discussions.]