<< Chapter < Page Chapter >> Page >

Natural sciences

Grade 8

Energy: electricity, heat and light

Module 4

Electricity

One of the forms of energy mentioned above is ELECTRICITY.

Electricity is an invisible form of energy that is related to the movement of very small particles. To understand this, one needs to understand the structure of an atom.

  • An atom is the smallest particle that any substance consists of. It comprises a nucleus of particles known as protons (positive) and neutrons (neutral), as well as a surrounding cloud of negative particles – electrons . The electrons move in an electric circuit.
  • In a neutral atom, the positive and negative particles are in balance.

Activity:

To make a drawing of the structure of an atom [lo 2.1, lo 2.3]

Assignment 1:

Ask your educator to explain the typical structure of an atom to you and then draw your own representation of it.

Assessment of the Sketch of an Atom

Were you able to draw the atom clearly.

[LO 1.2; LO 1.3]

The positive and negative particles in a neutral atom are usually in balance.

Activity:

To understand the concept of potential difference

[lo 2.1, lo 2.3, lo 2.4]

  • When an imbalance occurs, the negative electrons are set in motion.
  • Electricity can be conducted for great distances along wires. This energy can be converted to other forms of energy, like light, heat and movement by means of an appliance connected to the wires.
  • The electrons are not able to move by themselves but are pushed by the electric transfer that occurs. This “pushing” is known as the POTENTIAL DIFFERENCE (Pd).
  • This potential difference is usually produced by a power station or a battery. Inside the wiring, electrons will jump from one atom to another, like wagons of a freight train bumping against each other when force is applied at one end – it causes an impact that is transferred all along the wiring.

Assignment 1: Questions:

What is potential difference?

Find out what direct current is. Where is it used?

Assessment of Potential Difference

Were you able to answer the questions correctly?

[LO 2.1; LO 2.4]

Did you know?

  • There is a mild but similar electric current in the human body. It moves along the nerves in the form of pulses.
  • The machine that is able to detect and record this current is an EEG, (an electroencephalograph).
  • During an investigation with an electroencephalograph, electrodes with sensors are attached to the body.

Assessment

Learning outcomes(Los)

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.

Assessment Standards(Ass)

This is evident when the learner:

1.1 plans investigations;

1.2 conducts investigations and collects data;

1.3 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.

Assessment Standards(ASs)

This is evident when the learner:

2.1 recalls meaningful information;

2.2 categorises information;

2.3 interprets information;

2.4 applies knowledge.

Memorandum

Assignment 1:

One of the listed forms of energy is ELECTRICITY.

  • Electricity is an invisible form of energy that is based on the movement of very small particles. To understand this, one needs to understand the structure of an atom.
  • An atom represents the smallest particle that any substance consists of. It comprises a small nucleus of particles known as protons (positive) and neutrons (neutral), as well as a surrounding cloud of small negative particles – electrons . It is the electrons that move in the electric circuit.
  • In a neutral atom, the positive and negative particles are usually in balance.
  • When an imbalance is created, the negative electrons come into motion.n°
  • Electricity is the movement of energy along long lengths of copper wire and this energy can be converted to other forms of energy such as light, warmth and movement by means of any appliance connected to it.
  • The electrons cannot move by themselves; they are actually pushed forwards in the electric condition.
  • This “pressure” is known as the POTENTIAL DIFFERENCE (Pd).

éééé

The potential difference is usually produced by a power station or a battery.

  • In the wiring, electrons will literally bounce from one atom to another like the wagons of a freight train that bump against one another when force is applied at one end – it causes an impact that is transferred all along the wiring.

Do you know?

  • There is a mild but similar electric current in the human body, which moves along the nerves and muscles in the form of nerve and muscle pulses.
  • The machine that is able to pick up and record this is an EEG, an electroencephalograph. During such an investigation, electrodes with sensors that take readings are attached to the body.
  • Another application involves a pacemaker, which maintains the electrical impulses of the muscle tissue of the heart and supplements any inadequacy.

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




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