Energy Conversions

Energy Transfers and Conversions

Grade 4 science

What is energy?

Energy is the ability to do work or the ability to move an object. Energy cannot be made or destroyed; it can only be changed into different forms. Energy can be classified in two ways. First is potential energy, which is the amount of energy something has stored inside it. Next is kinetic energy. Kinetic energy is the energy of an object in motion. Anything that is moving has kinetic energy.

Let's review!

Energy Transformations include:

• sound

• light

• motion (known as Mechanical energy)

• heat

• electrical

Let's try applying our knowledge about energy transfer

Pick out the type of energy being transferred, where the energy is going/how it is transferring, or evidence that a transfer has taken place.

Multiple Choice

Which best describes and defines what is energy?

• A measure of the amount of matter inside an object

• Move from one place to another

• A measure of the capability to produce change

• Having the potential to develop into something great in the future

Multiple Choice

Which object is an example of a device that converts electrical currents into heat energy?

• a candle

• the sun

• a freezer

• a toaster

Multiple Choice

Juan is trying to build a device to transfer energy through electrical currents and needs to use a conductor to allow the electrons to flow easily. Which material should he choose to use in his design?

• cooper

• rubber

• plastic

• wood

Multiple Choice

Energy cannot be transferred from place to place by electric currents.

• True

• False

Multiple Choice

Jessica wants to transfer energy by electrical current for a class project. She begins observing simple household examples of electrical currents moving energy. Which answer choice is NOT an example of energy transferring through electricity?

• The doorbell ringing through the house from the front porch

• Pre-heating the oven to bake fresh cookies

• Lighting a candle when the power goes out to provide light

• Using an air conditioner to cool the house down in the summer

Multiple Choice

What is heat?

• Heat is the transfer of thermal energy.

• Heat is made up of waves of electromagnetic energy.

• Heat is the movement of energy by vibrations through substances in the form of waves.

• Heat is the flow of electrons – tiny, negatively charged particles in atoms.

Multiple Choice

How does heat energy move?

Hint: think of a pot of water how does it start out, then what happens to it after its on the stove?

• From cold objects to warm objects

• From warm objects to cold objects

• From small objects to large objects

• From large objects to small objects

Multiple Choice

What are the three ways that heat can move or transfer?

• Conduction, radiation, and temperature

• Kelvin, radiation, and convection

• Heat cannot be transferred or move in three ways.

• Conduction, radiation, and convection

Multiple Choice

Which of the following is an example of a good conductor of heat?

• clay

• plastic

• metal

• fabric

Multiple Choice

The measure of how hot or cold something is is called _______________.

• Kelvin

• Fahrenheit

• Temperature

• Temperature

Multiple Choice

What is sound?

• Sound is the movement of energy by vibrations through substances in the form of waves.

• Sound is the transfer of thermal energy.

• Sound is the flow of electrons – tiny, negatively charged particles in atoms.

• Sound is made up of waves of electromagnetic energy.

Multiple Choice

Which household item is an example of energy being transferred as sound?

• A hairbrush

• An alarm clock

• A candle

• A lamp

Multiple Choice

What must happen for sound waves to form?

• The intensity must largely increase.

• Sound waves are not reliant on anything to form.

• Matter must vibrate.

• The frequency must decrease.

Multiple Choice

Which of the following is an example of energy being transferred by sound?

• All of these are examples of energy being transferred by sound.

• A balloon popping

• Meat sizzling on the grill

• Tap dancing

Multiple Choice

Lower pitched sounds have a lower frequency than higher-pitched sounds.

• True because :

  The vibrations of low pitched sounds move molecules at a slower rate than the vibrations of higher-pitched sounds. This means that there is more time between vibration pushes. More time between pushes means that the frequency is lower.

• False:

  The vibrations can only occur at a fast rate, therefor they occur at a high frequently only, resulting in high pitches.

• False :

  The vibrations can only occur at a very slow rate, therefor they occur at a slow frequently only, resulting in high pitches.

• False because :

  The vibrations of low pitched sounds move molecules at a faster rate than the vibrations of higher-pitched sounds. This means that there is less time between vibration pushes. Less time between pushes means that the frequency is lower.

Multiple Choice

Moana says that an islander blowing on a conch horn is an example of energy being transferred by sound. Mowi says that Moana is wrong because a conch horn isn’t a real instrument. Based on what you know about the transfer of sound energy, which argument BEST supports why Moana's statement is correct?

• Even if a conch horn is not a typical instrument, blowing through it would still cause vibrations to travel through the air, which is how sound energy transfers.

• None of these arguments support that blowing on a conch horn is an example of energy being transferred by sound.

• Because conch horns originate in the ocean, they are full of the sounds of the water.

• A conch horn is a real instrument in certain countries, so Mowi is wrong.

Multiple Choice

What is light?

• Light is made up of waves of electromagnetic energy.

• Light is the transfer of thermal energy.

• Light is the movement of energy by vibrations through substances in the form of waves.

• Light is the flow of electrons – tiny, negatively charged particles in atoms.

Multiple Choice

Which of the following objects would better allow light to pass through?

Multiple Choice

Alexis has to identify an invention in her home that converts one energy form into another. She has selected the lightbulb. The energy input into a light bulb is electrical. What type of energy is output from a lightbulb?

• Light and motion

• Heat and motion

• Heat and light

• Sound and light

Multiple Choice

Allison has to design a device that converts energy between two different forms. She decides she wants to convert electrical energy into motion and sound. Which invention should she model her design after?

• An alarm clock

• An alarm clock

• A motor

• A radio

Multiple Choice

Mike designed a new firework for the holiday display. He spent weeks coming up with the perfect design to convert chemical energy into three forms of energy. Which three types of energy does a firework emit?

• Light, chemical, and sound

• Heat, light, and sound

• Sound, light, and mechanical

• Electric, sound, and heat