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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

how can chip be made from sand
Eke Reply
are nano particles real
Missy Reply
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
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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