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Natural sciences

Grade 9

Energy, forces and machines

Module 18



Naming, discussing and identifying energy sources and different forms of energy

[lo 2.2; lo 2.3; lo 2.4]

What is energy?

  • Energy is the ability to do work: to make things happen and to bring about change.

Forms of energy:

  • Energy occurs in different forms, e.g. as sound, warmth, light, chemical compounds and electricity.
  • Some objects have energy because they have motion, or simply because of their position. This has to do with kinetic energy (motion) or potential energy (position).
  • Energy cannot be seen or felt through touch, but is present everywhere: in the surrounding air, in each piece of matter, in each of the cells that make up our bodies. Energy is the only thing that existed before the big bang that marked the origin of the universe!

Sources of energy

  • Energy in ELECTROMAGNETIC form plays an important role in technological innovations like radio transmission towers, microwave ovens and X-ray machines.Scanners are machines that reveal images of things that are normally invisible, e.g. the internal organs of the body. The scanner sends sound waves into the body. When the patterns formed by the waves change, it shows an image that is of value in helping medical practitioners to make a diagnosis. The image that is produced is known as an MRI or Magnetic Resonance Image. This process is invaluable in the field of medicine.
  • We can distinguish three important sources of energy, namely:
  • the sun
  • atomic nuclei
  • the movement of the earth and its gravity, and the effect that other planets have on the earth.
  • Solar energy originates from the collision and fusion of atoms (nuclear fusion). This energy reaches us in the form of light and warmth. Heat energy causes atmospheric currents that result in wind, another important potential source of energy. Heat energy also results in evaporation of water, which leads to the formation of clouds which bring rain. When rain falls in high-lying areas, rivers are formed, yet another important source of energy.Solar energy is also captured in foodstuffs when photosynthesis occurs in plants. The food we eat and the fuel we use (e.g. petroleum) are derived from this process.
  • Nuclear energy is obtained when people use advanced technology to split atoms. Nuclear power stations convert nuclear energy into electrical energy.
  • The movement of the earth and its gravity, together with the influence that other planets exert on the earth , work together to create ocean currents and to cause the downward flow of rivers. Such energy can be utilised in different ways, e.g. for transportation or for driving machines, like turbines.

Try to identify the form of energy illustrated by each of the following examples and explain the sources of such energy.

Example of energy
  • a book lying partially overhanging the edge of a table
  • a cellular network sending sound waves to your cell phone
  • a ski-jumper jumping off a ski slope
  • an express train racing across the plains
  • heating your lunch in a microwave oven
  • a doctor taking x-ray photographs of your broken hand
  • a robot in a car manufacturing plant
  • a lightning bolt and a thunderclap
  • the energy in your lunchtime meal
  • sound that causes the eardrum to vibrate
  • electrical energy at Koeberg
  • the light of a torch

[LO 2.2; LO 2.3; LO 2.4]


Illustrating the law of energy conservation by means of different examples of energy conversion

[lo 2.4]

Conservation of energy

  • Herman Helmholtz (1821 – 1894) developed the law of ENERGY CONSERVATION.
  • This law states that ENERGY CANNOT BE CREATED OR DESTROYED . It can only be converted from one form to another.

Indicate the form of conversion that is relevant in each of the following instances:

  • A ball rolling from the top of a hill
  • A piece of wood burning
  • The ESKOM power stations
  • Pumping up your bicycle wheel
  • Sun panels attached to a satellite
  • A boy eating an ice-cream
  • A torch shining
  • A modern submarine travelling along the coastline
  • A person skating on ice
  • A water wheel
  • A pistol shot
  • A glowing electric light bulb

Write critical comments on the following statement: A steam train runs on solar energy .

Assessment of insight into the conservation of energy

Could you provide examples of the law of energy conservation?

[LO 2.4]


LO 2: Constructing Science Knowledge:

The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

This is evident when the learner:

  • categorises information;
  • interprets information;

2.4 applies knowledge.




Forms of energy illustrated:

  • Mill: Kinetic
  • Atomic bomb: Nuclear/atomic
  • Radio tower: Radiation
  • Heater: Radiation
  • Battery: Chemical
  • Light bulb: Radiation
  • Food: Chemical


Example Form Source
Book on table
  • Potential
Food supplied chemical energy by which the book was lifted onto the table through kinetic energy (the action of the muscles)
Ring of cell phone
  • Radiation
Chemical or nuclear: electricity
  • Potential and kinetic
Chemical (food or electricity) transported the person to a higher point
Express train
  • Kinetic / mechanical
Chemical or nuclear: electricity
Microwave oven
  • Radiation
Chemical or nuclear: electricity
X-ray plates
  • Radiation
Chemical or nuclear: electricity
Factory robot
  • Kinetic / mechanical
Chemical or nuclear: electricity
Lightning bolt
  • Radiation (warmth, light, sound)
Chemical: electricity
  • Potential, chemical
Chemical: sunlight that is held (in the food)
  • Radiation
Chemical: electricity
Electrical energy at Koeberg
  • Chemical / electrical
Light from a torch
  • Radiation (warmth, light)


  • Ball: potential to kinetic and sound
  • Wood: chemical / potential to sound, light, heat
  • Eskom: chemical / potential to electrical
  • Bicycle wheel: chemical / potential to kinetic/mechanical
  • Satellite: radiation to electrical
  • Ice-cream: chemical / potential to chemical / potential (stored in the body) to kinetic
  • Torch: chemical / potential to light and heat
  • Submarine: atomic / nuclear / chemical to electrical to kinetic
  • Skating: chemical / potential to kinetic
  • Water wheel: kinetic to electrical
  • Pistol: chemical / potential to kinetic, heat and sound
  • Light bulb: electrical to light and heat
  • Yes: Steam is derived from coal, which is dead plant material formed means of photosynthesis, with the help of sunlight (radiation by energy).

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Natural sciences grade 9. OpenStax CNX. Sep 15, 2009 Download for free at http://cnx.org/content/col11069/1.1
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