Unit 2.2 Conservation of Energy

Energy Transformations

Energy Transformations

Quick recap: what are the 7 main forms of energy?

Quick recap: what are the 7 main forms of energy?

• Chemical

• ​Sound

• Electrical

• Radiant/Light

• Mechanical

• Thermal

• Nuclear

The process of energy changing forms is called Energy transformations

You may also hear it referred to as Energy conversions

Law of Conservation of Energy

The law states: Energy cannot be created nor destroyed.

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In other words...

Energy can only change its forms from one type to another.

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The energy of the world is constant because of the total amount of energy does not change.

Some helpful hints

• If you have to plug it in ........ conversions likely starts with electricity

• If it is battery powered..... first 2 steps are chemical --> electrical

• If it produces electricity......... last step is likely electrical

Multiple Choice

Playing musical instruments:

____________ --> _________

• sound and light

• chemical and radiant

• kinetic and sound

• kinetic and thermal

Multiple Choice

Atomic bomb's energy transformation:

_______ --> kinetic, _______ and __________

• nuclear, sound, and thermal

• sound, light, and nuclear

• nuclear, chemical, light

• chemical, thermal, and sound

Energy Transformations can be multi-stepped.

Ex: Hairdryer

Electrical (plugging it in) --> Mechanical (spinning of the fan)--> Heat (hot air)

Multiple Choice

Food's energy transformation is:

________ --> thermal, _________

• chemical and kinetic

• chemical and radiant

• thermal and radiant

• sound and chemical

Let's look at a flashlight

• It runs on batteries (chemical energy)

• When it turns on, it's changed from chemical into electrical

• Then, it is transformed into light energy.

Multiple Choice

The sun's energy transformation is:

________ --> thermal and _________

• nuclear and light

• nuclear and chemical

• chemical and light

• light and nuclear

Multiple Choice

A tree's energy transformation is:

_______ --> _________

• light and sound

• light and chemical

• nuclear and sound

• nuclear and chemical

Name the conversions

Multiple Choice

Which specific type of energy is at point A?

• Potential Energy

• Kinetic Energy

• Mechanical Energy

• None

Multiple Choice

If a lot of the energy that you put in isn't wasted, then the machine is .......................................

• efficient

• not efficient

Multiple Choice

The Law of Conservation of Energy states:

• Energy can created or destroyed but not transformed 

• Energy cannot be created or destroyed, it can only transformed

• Energy can't be created, destroyed or transformed

Multiple Choice

The SI Unit for Energy is

• Joule

• Potential

• Calorie

• Kilojoule

Multiple Choice

If the Total Mechanical Energy is 50J, Potential Energy is 40 J, what is the Kinetic Energy?

• 1 J

• 10 J

• 90 J

Multiple Choice

Which specific type of energy is at point B?

• Potential Energy

• Kinetic Energy

• Mechanical Energy

• None

Multiple Choice

What is the wasted energy here? (we want light)

• electrical

• heat

• movement

Multiple Choice

What is the wasted energy here? (we want movement)

• heat, light and sound

• chemical, electrical and movement

• Sound, sound and sound

Multiple Choice

What type of device might this Sankey be about?

• A very efficient LED light bulb

• A very inefficient incandescent light bulb

• A coal power plant

• A wind turbine

Multiple Choice

Which bulb is the most efficient?

• Filament bulb

• LED light

• CFL lamp

Multiple Choice

In an electric drill, the input energy is electrical energy. Which of these is wasted output energy?

A – Sound energy B – Kinetic energy C – Heat energy

• A, B

• A, C

• B, C

• B

Multiple Choice

The equation KE = 1⁄2 mass x velocity² is used to find which type of energy?

• Kinetic Energy

• Potential Energy

Multiple Choice

The equation PE = mass x gravity x height is used to find which type of energy?

• Kinetic Energy

• Potential Energy

Multiple Select

Kinetic energy depends on the ________ and ________ of the object.

• Height (position)

• Mass

• Speed

• Friction

Multiple Choice

The faster an object moves, the ________ kinetic energy it has.

• more

• less