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Natural sciences

Grade 9

Energy, forces and machines

Module 24



Identifying levers as mechanisms to identify energy transfer

[lo 2.2; lo 2.3; lo 2.4]

The operation of the simple appliances given above depends on the principle of the lever.

  • All levers have a PIVOTAL POINT or FULCRUM , a point where effort or power is applied (or the POWER POINT) , and an AREA OF LOAD called LOAD (L) .
  • The relevant symbols are:
  • P = point/fulcrum
  • E = effort/power
  • L = load
  • Levers are classified according to the position of the fulcrum.
  • There are three classes of levers.
  • Class 1 lever
  • Class 2 lever
  • Class 3 lever

CLASS 1: Fulcrum in the middle

e.g. a see-saw

CLASS 2 : Load in the middle

e.g. a wheelbarrow being pushed

CLASS 3: Effort/Power in the middle

e.g. a golf club or broom held for use

Identify the class of lever in each of the following examples:

a) You pick up a can of cold drink and raise it to your mouth.

b) You stand on the tips of your toes.

c) You hold a fishing rod, having hooked a large fish.

d) You row a boat using an oar.

Assessment of classification of LEVERS

Were you able to place the examples in categories?

[LO 2.2; LO 2.3]


Calculating mechanical advantage

[lo 2.4]

Force × distance = load × distance

  • It is possible to calculate the mechanical advantage of a lever: the ratio of load to force provides this index.
  • We refer to this as mechanical advantage.

1. How would one be able to enhance the mechanical advantage of a class 1 lever?

  1. You have a nutcracker with the following dimensions:
  • You require 150 N to crack the nut.

a) Which FORCE is needed?

b) What is the mechanical advantage of the nutcracker?

[LO 2.4]

The Wheel


Researching the invention of the wheel and evaluating as an example of human endeavour

[lo 1.1; lo 1.2; lo 2.1]

The invention of the wheel more than five thousand years ago resulted in a remarkable change in human performance of work.

The wheel is like a lever, except that the movement comprises rotation around an axle and not an up and down movement around a fulcrum.

Project dealing with the WHEEL

Work as a group and create a poster to represent the development of the wheel and to illustrate different ways of using wheels.

  • Did the Egyptians have wheels to assist them when they were building the pyramids?
  • How did they manage to perform all these tasks?

Assessment of RESEARCH on the WHEEL

Were you able to plan and execute the investigation and to evaluate it?Were you able to gain INSIGHT into the VALUE of human scientific endeavour?

[LO 1.1; LO 1.3; LO 3.1]


LO 1: Scientific investigations:

The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

This is evident when the learner:

  • plans investigations;
  • conducts investigations and collects data;
  • evaluates data and communicates findings.

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:

  • recalls meaningful information;
  • categorises information;
  • interprets information;

2.4 applies knowledge.

LO 3: Science, Society and the Environment

The learner will be able to demonstrate an understanding of the interrelationships between science and technology, society and the environment.

This is evident when the learner:

3.1 is able to show an appreciation of science as a human endeavour.



a) Class 3

b) Class 2

c) Class 3

d) Class 1


L.W. A study of levers is no longer required as part of the syllabus, but levers are referred to in this module to illustrate the transfer of energy from one body to another.

1. Reduce the force distance

2. a)



Assess according to the learning outcomes and assessment standards indicated in the module.

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
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
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
How can I make nanorobot?
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
how can I make nanorobot?
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
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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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