This document discusses work, energy, and the different forms of energy. It defines work as force applied over a distance, with the unit of measurement being joules. Energy is defined as the ability to do work and also measured in joules. There are different forms of energy including kinetic, potential, thermal, sound, electric, chemical, and nuclear. The principle of conservation of energy states that energy cannot be created or destroyed, merely transformed between forms. Examples are given of energy transformations and students are asked to identify the energy changes in various scenarios. An interactive simulation is provided to allow students to investigate energy transformations further.

1. Work and
Energy

2. Activity:
► Place the palms of your hands
against a (sturdy) wall and push with
all your strength for 10 seconds.
► Do you feel tired? How would you
feel if you had pushed for 10
minutes?
► Did you do any work while you were
pushing?

3. Work
► Work is done when a force is
exerted and there is a change
in position.
► Work is the product of a force
and the distance moved in the
direction of the force.
► work = force x displacement
► The SI unit of Work is the joule, J
► 1 J = 1 Nm

4. Worked Example
► Chris pushes a block 25 m across a smooth
floor with a horizontal force of 20 N.
Determine how much work was done.
Solution:
work = force x displacement
W = F x d
W = 20 N x 25 m
W = 500 Nm
= 500 J

5. Activity: How would you sort the following
pictures into 2 groups?
HEAT
SOIL
METAL
WATER
SOUND
LIGHT

6. HEAT
SOIL
METAL
WATER
SOUND
LIGHT
ENERGY MATTER

7. Energy
► Energy is the ability to do work.
► Energy is also measured in
joules.
► Energy can take different
forms.

8. Forms of Energy
► Follow the link below to a YouTube
video describing the different forms
of energy.
https://www.youtube.com/watch?v=86PzkR
bw4_U

9. Test Your Understanding
► For each of the 9 forms of energy in
the table below, match the form of
energy on the left to the correct
descriptions on the right.

10. Form of Energy Description
1 Kinetic A The energy of an object as a result of its position or height.
e.g. a bucket about to fall from a ladder.
2 Sound B The energy of an object as a result of its condition.
e.g. a compressed spring or a stretched rubber band
3 Heat (or Thermal) C The energy stored in the bonds of chemical compounds. e.g. food
or fuel
4 Electric D The energy transferred by the vibrating particles of a sound wave.
5 Nuclear E The energy due to the motion of the particles (molecules) of a
substance or body.
6 Gravitational
Potential
F The energy resulting from charged particles in an electric field.
7 Chemical G The energy binding the particles of the nucleus of an atom.
8 Elastic Potential H The energy resulting from the vibration of electric and magnetic
fields. e.g. visible light, radio waves, microwaves.
9 Light (or
Electromagnetic)
I The energy of an object as a result of its motion.

11. Answers
Form of Energy Description
1 Kinetic I The energy of an object as a result of its motion.
2 Sound D The energy transferred by the vibrating particles of a sound wave.
3 Heat (or Thermal) E The energy due to the motion of the particles (molecules) of a substance or
body.
4 Electric F The energy resulting from charged particles in an electric field.
5 Nuclear G The energy binding the particles of the nucleus of an atom.
6 Gravitational Potential A The energy of an object as a result of its position or height.
e.g. a bucket about to fall from a ladder.
7 Chemical C The energy stored in the bonds of chemical compounds. e.g. food or fuel
8 Elastic Potential B The energy of an object as a result of its condition.
e.g. a compressed spring or a stretched rubber band
9 Light (or
Electromagnetic)
H The energy resulting from the vibration of electric and magnetic fields. e.g.
visible light, radio waves, microwaves.

12. The Principle of Conservation of Energy
► This states that energy cannot be created or destroyed but is instead
transformed from one type of energy to another.
► Take a look at this YouTube video about the Conservation of Energy
https://www.youtube.com/watch?v=k4b3oxO0WqE

13. Examples of energy conversions
1. A coconut falling from a tree and striking the ground below (not rebounding):
gravitational potential kinetic sound + thermal
2. A gasoline-fueled car accelerating on a level road:
chemical kinetic + sound + thermal
3. An aircraft taking off:
chemical kinetic + gravitational + sound + thermal
* Note that thermal energy is a product of all energy transformations.

14. Test your understanding
► Identify the energy changes in the following scenarios.
1. A battery charging
2. An electric fan that is plugged in and switched on.
3. An electric oven
4. A microphone
5. A loudspeaker

15. Answers
1. A battery charging: electric to chemical and heat
2. An electric fan that is plugged in and switched on : electric to kinetic and sound and heat
3. An electric oven: electric to heat and light
4. A microphone: sound to electric and heat
5. A loudspeaker: electric to sound and heat

16. Activity
► Click on the link below and use the
PhET Simulation to investigate energy
transformations.
► https://phet.colorado.edu/sims/html/ene
rgy-forms-and-changes/latest/energy-for
ms-and-changes_en.html

17. Closure
Before we go, think about today’s lesson
and type the following inti the chat:
► Two new things I learned.
► One question I still have.