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Grade 8


Module 12

The nature of electrical current


In order to realize how essential electricity is to ones life, just turn off the electricity supply to your home for a while. It is difficult to realize that there are still people who get along without electricity, but usually even those people have battery-driven radios. Fortunately, most homes in South Africa have electricity. This commodity helps to improve people’s standard of living.

Activity 1

To demonstrate knowledge and understanding of the nature of electrical current, where it comes from, and the positive and negative impact thereof on the environment

LO 2.4 LO 3.2

ElectronProtonCoreNeutronElectron circuit

The atom is the building block of all material and it consists of the following parts: a core with protons and neutrons, and electrons that revolve in an orbit around the core. Electrons can be separated from the core and are then known as free electrons. When the free electrons move in the same direction, an electron flow (an electrical current) is formed.

There are two kinds of electrical currents, Alternating Current (AC) and Direct Current (DC). We mainly use alternating current in our homes for our stoves, refrigera­tors and lights. The electricity comes from a power-station, but many of the items in the home, for example torches, work with DC that comes from batteries. Many items such as cellular phones use AC to recharge their batteries that provide DC.

Assignment 1

1.1 How does electricity improve our standard of living / quality of life? (1 paragraph)

1.2 Provide the symbols for AC and DC. (Look at the back of your radio.)

1.3 How strong is the alternating current that is commonly used in South Africa?

1.4 Which company provides electricity in South Africa?

1.5 Name the different methods used by this company to generate electricity.

1.6 Choose one of the methods mentioned in 1.5 and describe the negative impact that the provision of this method of generation of electricity has on the environment.

1.7 Draw a diagram to represent the route that the power to your town/city/settlement follows from the power-station to your house.

LO 2.4 LO 3.2


Learning outcomes(LOs)
LO 2
TECHNOLOGICAL KNOWLEDGE AND UNDERSTANDING The learner will be able to understand and apply relevant technological knowledge ethically and responsibly.
This is demonstrated when the learner:
structures:2.1 demonstrate knowledge and understanding of frame structures:
  • the use and application of basic structural components (columns, beams, arches, buttresses, struts, stays, guys, ties);
  • reinforcing techniques for frame structures (triangulation, webs and fillets, orientation and cross-sectional area and members);
  • how frame structures can be made strong (e.g. relationship between the size and the shape of the base, the centre of gravity and stability;
systems and control:2.4 demonstrates knowledge and understanding of how electrical circuits with more than one input or control device will work based on different logic conditions (“AND” and “OR” logic), and represents them using circuit diagrams, systems diagrams and truth tables.
LO 3
TECHNOLOGY, SOCIETY AND THE ENVIRONMENT The learner will be able to demonstrate an understanding of the interrelationships between science, technology and the environment.
This is demonstrated when the learner:
impact of Technology:3.2 expresses and details opinions about the positive and negative impacts of products f technology on the quality of people’s lives and the environment in which they live.



  • The emphasis should be on the origin of electricity, namely the atom. Learners should also become thoroughly acquainted with the difference between AC and DC.

Assignment 1

1.1 Emits light and warmth. Can be used in electrical appliances, e.g. TV sets, computers, etc.

1.2 AC

1.3 220V


1.5 Nuclear power stations, hydroelectricity, coal-driven power stations, wind turbines.

1.6 Nuclear power: nuclear waste; radiationHydro power: disrupts ecologyCoal: smoke pollutionWind turbines: intrudes on the landscape

1.7 The emphasis should be on power lines, substations and transformers.

Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
I'm not good at math so would you help me
what is the problem that i will help you to self with?
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele 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, Technology grade 8. OpenStax CNX. Sep 13, 2009 Download for free at http://cnx.org/content/col11052/1.1
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