<< Chapter < Page Chapter >> Page >

Natural sciences grade 8

Energy: electricity, heat and light

Module 1: energy to begin

Energy is derived mainly from the sun and is available to us in various forms.

Some facts concerning energy:

  • Energy is the capacity for doing work . We measure energy in joule (J).
  • There are two main types of energy:
  • The energy of action or motion is known as KINETIC energy
  • The energy of position is known as POTENTIAL energy
  • Energy also occurs in various forms, e.g.:

Chemical energy, which is obtained from chemical substances like petroleum, oil, gas, batteries and foodstuffs;

Electrical energy, which is derived from electricity;

Sound energy, from loudspeakers

Radiant energy, from light and heat. The sun is our largest source of radiant energy.

Nuclear energy , is stored in the nucleus of the atom.

Energy cannot be created or destroyed. It can only be converted from one form to another.

Activity:

To identify the different types of energy

[lo 2.1, lo 2.2, lo 2.4]

Assignment

In the following list, indicate the form of energy that is present:

  1. Car battery
  2. Paraffin stove
  3. Wind-up toy car
  4. Hair drier
  5. Rubber band (shooting)
  6. Radio
  7. Food
  8. A growing plant
  9. Burning candle
  10. Nuclear power station

Assessment of forms of Energy

Were you able to indicate the forms of energy correctly?

[LO 2.2]

Assessment

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;

2.4 applies knowledge.

Memorandum

Assignment:

1. Car battery – CHEMICAL to ELECTRICAL

2. Paraffin stove - CHEMICAL TO HEAT

3. Wind-up toy car – POTENTIAL TO KINETIC

4. Hair dryer – ELECTRICAL TO HEAT

5. Elastic band (being shot) - POTENTIAL TO KINETIC

6. Radio – ELECTRICAL TO SOUND

7. Food – CHEMICAL TO KINETIC

8. A growing plant – RADIANT TO KINETIC

9. Burning candle – CHEMICAL TO LIGHT AND HEAT

10. Nuclear power station – KINETIC TO ELECTRICAL

  • Explain this to grade 8 with the help of a simple example.
  • It is generally known that the common light bulb provides us with light, but also becomes so hot that it can hardly be touched after a few moments. Approximately 100J of electric energy are converted to light energy AND heat energy within one second. The light energy has the value of about 5J, while the heat equals about 95J.
  • The conversion therefore is as follows:
  • ELECTRIC ENERGY TO LIGHT ENERGY AND HEAT ENERGY
  • A light bulb therefore is altogether uneconomical!
  • If you consider this, you will realise that the food provides the SOURCE OF ENERGY of human beings, but electricity and fuels provide all other aspects of energy. This brings us to the next learning unit.

Questions & Answers

Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
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.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
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
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
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 8. OpenStax CNX. Sep 12, 2009 Download for free at http://cnx.org/content/col11050/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Natural sciences grade 8' conversation and receive update notifications?

Ask