<< Chapter < Page Chapter >> Page >

Natural sciences

Grade 9

Energy: forces and machines

Module 21

Work and conversion of energy

Activity 1:

Describing the relationship between effort and energy with reference to a turbine

[LO 1.2, 2.1, 3.2]

Energy is necessary for any performance of work. This energy must be obtained from FUELS or from CONVERTED forms.


  • Use a tin lid, cut it into segments to form it into a fan and make a hole in the centre.
  • Nail the fan to a piece of wood.
  • Boil water in a kettle, until there is a strong draught of steam.
  • Hold the fan in position so that the jet of steam will be directed towards its centre.

1. What happened?

2. What kind of energy conversion occurred?

3. Describe the form of energy conversion that occurs with wind towers such as those that have recently been erected along the West Coast in the vicinity of Malmesbury.

4. What advantages do wind towers like these have for the environment?

  • Write a paragraph (60 words) about the value that the principle of the turbine has for people.
  • WORK is also measured in (give the name of the unit) .…………....................................

Activity 2

Discussing other machines that operate by means of conversion of energy


  • As long ago as the early 17 th century, Robert Hook assumed that light rays have energy and that a wound-up spring has potential energy. He also constructed the first microscope and was the first person to use the universal lever, which is used in a wide range of instruments and cars.


  • Satellites depend on solar panels to absorb light energy from the sun and supply electricity for all other electronic functions and for cameras and radio equipment. Energy is also stored in chemical form in rechargeable batteries.


  • The blades of the rotary disk are turned by the wind to drive a pump that pumps underground water to a storage dam.


  • Name at least three other machines that operate by means of energy conversion and explain the workings of each one.


  • When a machine or appliance fails to provide an adequate quantity of the energy that it has been designed to provide we say that it is in affective.
  • The light bulb, for instance, releases (unwanted) heat, but was actually designed to provide light!
  • In this instance, fluorescent lighting is more effective and economical.
  • Are you able to list further examples?


LO 2
Scientific KnowledgeThe learner will know and be able to interpret and apply scientific, technological and environmental knowledge.
This is displayed when the learner:
2.1 is able to recall meaningful information;
2.2 is able to arrange information according to categories;
2.3 is able to interpret information;
2.4 is able to apply knowledge.
LO 3
Science, Environment and the CommunityThe learner will be able to demonstrate an understanding of the interrelationships between science and technology, society and the environment.
This is displayed when the learner:
3.1 is able to show appreciation of science as a human endeavour;
3.2 is able to recognise the value of sustainable utilisation of resources.


Activity 1


1. The fan (‘turbine’) rotates

2. Chemical to steam to kinetic / mechanical

3. Kinetic to electrical to chemical

4. Natural resources (e.g. coal) are not used and pollution is avoided


  • E.g. natural energy is converted to usable energy
  • Without consumption of resources
  • Without pollution
  • There are no waste products to be got rid of
  • Examples of utilising turbines: generation of electricity, previously also for driving mills

Effort is measured in Joule

Activity 2

  • Any power generator
  • Compressor
  • Vehicle engine
  • Sewing machine
  • Kitchen appliances
  • Etc.
  • Ineffective machines: any machine or system that releases energy in a non-usable form, e.g. a car that is driven with the hand break on (much energy is wasted in the attempt to overcome the force of friction – energy in the form of heat goes to waste).

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
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Natural sciences grade 9. OpenStax CNX. Sep 15, 2009 Download for free at http://cnx.org/content/col11069/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Natural sciences grade 9' conversation and receive update notifications?