Forms of Energy

Energy types

Energy transfers

Wasted energy

Joules

Exercise 1: Types of Energy 1

Many objects EMIT(GIVE OUT) light. This is a type of

electromagnetic radiation.

All sounds are caused by VIBRATIONS. The LOUDER a sound, the MORE energy it has.

This is the energy possessed by an object due to its MOVEMENT. The FASTER an object moves,

the MORE energy it has.

Kinetic Energy

Sound Energy

Light Energy

Exercise 2: Types of Energy 2

This is the energy stored in the NUCLEI of atoms.

This is the energy an object possesses due to it being

STRETCHED or SQUASHED.

The HOTTER an object is, the MORE of this energy it has.

Thermal Energy

Nuclear Energy

Elastic

Exercise 3: Types of Energy 3

This is the energy possessed by FLOWING ELECTRONS

(ELECTRICAL CURRENT).

The is the energy an object possesses due to its position in a GRAVITATIONAL FIELD. The

HIGHER an object is in the field, the MORE of this energy it has.

This is the energy stored in FUELS, FOOD and BATTERIES. It is released through CHEMICAL

REACTIONS.

Electrical Energy

Chemical Energy

Gravitational Energy

Exercise 4: Forms of Energy

1. Which type of energy is emitted by the Sun, lamps and stars?

2. Which type of energy is stored in the nuclei of atoms?

3. Which type of energy is stored in food, fuels and batteries?

4. Which type of energy is possessed by flowing electrons?

5. Which type of energy is possessed by an object that is being stretched or compressed ?

Light.

Nuclear.

Chemical.

Electrical.

Elastic.

Exercise 5: Forms of Energy

1. What happens to the gravitational energy of an object as it gets higher in a gravitational field?

2. What happens to the kinetic energy of an object as it moves faster?

3. Which type of energy are kettles, irons and Bunsen burners designed to produce?

4. Which sounds have the most energy, loud or quiet?

It increases.

It increases.

Heat.

The louder the sound, the more energy it has.

Exercise 6: Link the Diagram with the Energy

Sound Chemical Light Kinetic

Energy ChangesEnergy CAN NOT be CREATED or DESTROYED; it can only be CHANGED IN FORM.

Many devices convert energy from one form to another. ELECTRICITY is a VERY USEFUL form of energy because it is VERY EASY to convert from one form to another.

What is the energy transfer for a lamp?

Start energy?

End energy?

Electrical energy

Light energy

Exercise 7: Transfers

1. Name three devices that use electrical energy.

2. Why is electrical energy so useful?

3. What is the main energy transfer for a catapult?

4. What is the main energy transfer for a coal fire?

5. What is the main energy transfer for a solar cell?

6. What is the main energy transfer for a television?

TV, radio, cooker, iron, microwave, freezer.

It is easy to transfer from one form to another.

Elastic to kinetic.

Chemical to heat.

Light to electrical.

Electrical to light and sound.

Wasted EnergyWhenever an energy transfer occurs some energy is ALWAYS WASTED. Where does this energy go to?

It SPREADS OUT and is LOST to the SURROUNDINGS. It is very hard to REUSE. This is why we should be mindful not to waste energy needlessly.

What is the wasted energy for an electrical lamp?

A lamp is designed to change electrical energy into light energy.

Some energy is wasted in the form of HEAT though. In fact, ALL ELECTRICAL devices WASTE ENERGY in the form of HEAT.

If you could hear the lamp buzzing then it would be wasting energy in the form of SOUND.

Exercise 8: Wasted Energy

1. What happens to wasted energy?

2. In which two forms is energy usually wasted?

3. In what form do all electrical devices waste energy?

4. If you can hear a device that is not supposed to make a noise, in what form is energy being wasted?

5. In what forms does a hairdryer waste energy?

6. In what form does a coal fire waste energy?

It spreads out into the surroundings and is harder to reuse.

Heat and sound.

Heat.

Sound.

Heat and sound.

Light energy.

Exercise 9: Link the Device with the Main Energy Change

Sound to electrical

Electrical to sound

Light to electrical

Electrical to heat

Elastic to kinetic

Kinetic to electrical

Microphone

Loudspeaker

Catapult

Kettle

Wind turbine

Solar cell

Exercise 10: Units of Energy

What are the units of energy? JOULES (J)

1. A radio converts 300J of electrical energy into 120J of sound energy.

a) In what form is energy wasted by the radio?

b) What happens to this wasted energy?

c) How much energy is wasted?

d) In what other form is energy usually wasted by devices?

Heat.

Spreads out into surroundings and is harder to reuse.

180J.

Sound.

Exercise 11: A Car Engine

1. A car engine uses the fuel petrol. The car converts 400J of the energy stored in petrol into 100J of kinetic energy.

a) What energy is stored in petrol?

b) In what forms is energy wasted by a car engine?

c) How much energy is wasted by the car engine?

d) What percentage of useful energy is transferred by the engine?

Chemical.

Heat and sound.

300J.

25%.