2.2 Energy adds up (Conservation of energy)

Conservation & transfer of energy

Lesson objectives; You'll be able to

https://youtu.be/Um04eHOqGlM

• Describe energy before and after a change

• Explain what brings about changes in energy

Law of conservation of Energy

Energy cannot be created or destroyed, only transferred from one form to another.

Some forms of energy include;

Mechanical ~ moving objects, Thermal ~ moving molecules,

Electrical ~ moving electrons, Electromagnetic ~ moving waves, Nuclear energy.

Multiple Choice

Quick recap; Fill in the blanks

Energy cannot be created or _______, only transferred from one form to another.

• Created

• Removed

• Added

• Destroyed

Multiple Choice

Quick recap; Fill in the blanks

Energy cannot be created or destroyed, only ________ from one form to another.

• Created

• Transferred

• Destroyed

• Form

Multiple Choice

Quick recap;

True or False; The law of conservation of energy states that Energy can be created or destroyed, and transferred from one form to another.

• True

• False

Multiple Choice

Which of the following is an example of energy transfer?

• A big truck colliding into a small car

• Sun's heat making me hot

• Microwave heating up food

• All of these

Multiple Choice

Which of the following forms of energy involves moving people?

• Electrical

• Nuclear

• Thermal

• Kinetic

Energy stores (Page 142)

You can think of energy as being in store, when it is needed, it is transferred from the store into another form to be used.

Here are some types of energy stores;

Chemical store →→→→→ food, fuels, batteries

Thermal store→→→→→ hot objects

Kinetic store →→→→→ moving objects

Gravitational potential store →→→→→ height or position in a gravitation field

Elastic store →→→→→ changing shape, stretching, or squashing

https://www.bbc.co.uk/bitesize/topics/zc3g87h/articles/zg2sn9q

Open Ended

Give three examples of energy stores, and the type of energy stored there

Multiple Choice

Making deductions;

How can you increase the potential energy stored by an object in a gravitational field?

• Increasing the height

• Decreasing the height

• Heating up the object

• Adding a current to the object

Multiple Choice

Making deductions;

In a rubber band car, the kinetic energy of the car can be increased by increasing the elastic potential energy of the rubber band. How can one do this?

• Using bigger tyres (bottle caps)

• Winding the rubber band more times

• Winding the rubber band less times

• Using more glue and stronger sticks

Multiple Choice

Read Page 142;

If you could measure the total energy in a the chemical and thermal stores, you would find that;

• Total energy before ≠ Total energy after

• Total energy before > Total energy after

• Total energy before < Total energy after

• Total energy before = Total energy after

Multiple Choice

True or False;

Electric current, light and sound are ways of transferring energy between stores. (Page 143)

• True

• False

Multiple Choice

After you use your phone, there is ____ energy in the thermal store of the surroundings (Page 143)

• Less

• More

Multiple Choice

What do scientists mean when they say energy is dissipated? (Page 143)

• Energy is transferred to useful forms

• Some energy is transferred to the thermal stores of the surroundings

• Energy is used to move the car

• Energy is transferred to the kinetic store of the car

Multiple Choice

Another way to say "Energy is dissipated" is...

• Energy is wasted

• Energy is used up

• Energy is transferred

• None of these

Multiple Choice

Which of the following explains why things happen? (Page 143)

• Energy

• Current

• Forces

• All of these

Open Ended

Answer both parts

a) Describe where and how energy is stored in a torch

b) Explain what happens to the Energy stored in a torch when it is switched on.

Multiple Choice

HW 1;

What is the unit oe energy?

• Watt (W)

• Newton (N)

• Joule (J)

• Kilogram (Kg)

Multiple Choice

HW 2;

The energy in which store increases as a car moves faster?

• Gravitational potential energy

• Thermal energy

• Chemical energy

• Kinetic energy

Multiple Choice

HW 3;

The energy in which store decreases as a candle burns? 

• Chemical energy store

• Nuclear energy store

• Elastic energy store

• Thermal energy store

Multiple Choice

HW 4 ;

The energy in which store increases as an elastic band is stretched? 

• Gravitational potential energy store

• Electromagnetic energy store

• Kinetic energy store

• Elastic potential energy store

Multiple Choice

HW 5:

_________________ is when energy is transferred because a force moves an object through a distance. 

• Heating

• Mechanical working

• Heating

• Radiation

Multiple Choice

HW 6;

_______________ is when energy is transferred due to charge flowing. 

• Electrical working

• Static charge working

• Radiation

• Electromagnetism

Multiple Choice

HW 7;

________ is when energy is transferred between areas that have different temperatures. 

• Radiation

• Heating

• Mechanical working

• Electrical working

Multiple Choice

HW 8;

________________ is when energy is transferred due to a wave being emitted.

• Electrical working

• Nuclear working

• Electromagnetic radiation

• None of these

Multiple Choice

HW 9;

When a kettle boils, how is energy transferred to the surroundings?

• By light

• By heating

• By electrical working

• By mechanical working

Multiple Choice

HW 10;

What are two examples of energy transfer by radiation?

• Mechanical working and light

• Light and sound

• Lectrical working and sound

• Heating and mechanical working