ACTIVITY 1:

To discuss electricity as a form of energy

[LO 1.1.1; LO 1.2.1; LO 2.1; LO 3.1]

The importance of electricity

In our modern society, life without electricity is unthinkable.

Make a list of daily activities for which you or your family use electricity.

Everyone might list the use of light. Let us take a look at our well-known light bulb.

Bring an electric light bulb to school to help you with the following task.

The tungsten filament has to be long and thin to be able to glow brightly. Fitting a long enough filament into the globe requires it to be coiled. Because it is long, it is also relatively heavy for something as fine and it therefore needs the support of a stronger wire.

The power of the light bulb is indicated on the bulb in “watt”. Household light bulbs come in 40W (dim), 60W (the most generally used), 75W, 100W or 150W (the brightest).

Figure 1

Take a look now at the light bulb that you have brought with you.

enter the light bulb?

The generation of electricity

Remember that we use electricity to obtain ENERGY.

The advantage of electricity is that it makes us less dependent on fuels from natural resources. These fuels are being rapidly depleted. Let us take a look at a few manners in which electricity can be generated

A dynamo can be used as a generator, for example by a cyclist at night. Do some research and explain briefly how a dynamo works. Remember to say where the energy comes from.

Figure 2

A hydroelectric power station makes use of moving water to generate electricity. The water is led through pipes to turn turbines. The turbines turn generators (almost like the dynamo of the bicycle). The greater the pressure of the water that flows through the pipes, the more electricity is generated. It is therefore important to ensure that enough water is dammed up by building walls across rivers so that the river water can accumulate behind the wall.

Cape Town obtains a portion of its electricity from turbines in the mountains near Somerset West.

Figure 3

Write ten sentences about each of the following:

What is energy?

Activity 2:

To explain the term energy

[LO 2.1]

LEARNING OUTCOME 1:

SCIENTIFIC INVESTIGATIONSThe 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

We know this when the learner:

1.2.1 follows instructions for setting up apparatus and executing observations;

1.2.2 collects data from observation by means of sketches and labels;

1.2.3 perseveres until a result is obtained or continues to observe over an extended period of time;

1.3 evaluates data and communicates findings: provides feedback on progress in group context, as well as the eventual result:

1.3.1 presents data obtained from observation that are relevant to the target question.

LEARNING OUTCOME 2:

ConstructinG scienCE knowledgeThe learners will know and be able to interpret and apply scientific, technological and environmental knowledge.

ASSESSMENT STANDARDS

We know this when the learner:

2.1 recalls meaningful information: the minimum requirement is the ability to describe the features and characteristics of objects, materials and organisms in simple terms.

2.1.3 say whether energy can be converted from one form to another.

LEARNING OUTCOME 3:

Science, SOCIETY and the environmentLearners are able to show understanding of the underlying connections of technology, the community and the environment.

ASSESSMENT STANDARDS

We know this when the learner:

3.1 understands science and technology in the context of history and indigenous knowledge:

3.1.1 describes traditional shelters and connects some features of such shelters with modern dwellings.

Activity 1

The list is limitless, for example stove, refrigerator, light, electric razor, hair drier, kettle, toaster, starter of a car engine, etc.

Light bulb:

1. For example 100. How much energy is emitted by the lamp in the form of light, or how brightly the lamp shines, etc.

2. The bulb is inserted so that it fits tightly; two pins hold the bulb in position. Or the bulb screws in and is held in position in this way.

3. Two little contact points or one point and the side of the part with the screw-thread (socket).

4. Metal that conducts electricity.

5. To prevent a short-circuit or to ensure that the current flows through the filament.

6. It is rolled up and is curved so that it is as long as necessary to provide the amount of light that is indicated by the Watt.

Labels:

Assignment:

These are open questions and it must be left to the learners to formulate their own ideas. Allow them to put across their ideas to the class and allow time for discussion.

Activity 2

1. Energy is the ability to do work.

2. Yes. Electrical energy in light energy or heat energy; stored energy in food to heat energy or motion energy; etc.

3. No. Energy comes from nature, mainly the sun, and one can merely convert it into a useful form.