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Electricity as a form of heat

Module by: Siyavula Uploaders. E-mail the author

NATURAL SCIENCES

Grade 5

ENERGY AND CHANGE

Module 36

ELECTRICITY AS A FORM OF ENERGY

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.

  • The light bulb is a good example of an invention that drastically changed the lifestyle of man. A person with the name of Thomas Alva Edison invented it approximately 100 years ago.

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

  • If you examine an electric light bulb, you will notice that the part that emits light is a fine wire, the filament. The filament is a very fine coil made of tungsten. Tungsten is a metal that does not melt easily when it gets hot and glows. There is no air inside a light bulb, only a harmless gas called argon, which prevents the filament from being destroyed when it burns.

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
Figure 1 (graphics1.png)

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

  1. The bulb is watt. What does it tell you?

  1. How does your light bulb fit into the holder?

  1. Look at the narrowest part of the light bulb. At which point does the power

enter the light bulb?

  1. What is this section made of?
  2. Why are the supporting wires separated by means of a glass support?

  1. The tungsten filament is formed in a particular manner and supported by wires. Why?

  1. Sketch your light bulb and supply the necessary labels. Refer to the story for help.

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

  • The dynamo

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
Figure 2 (graphics2.png)
  • Generating electricity by means of water in streams and rivers

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
Figure 3 (graphics3.png)
  • Assignment

Write ten sentences about each of the following:

  • How people generated electricity in the past and how it is done today.

  • How electricity has changed our lifestyle.

  • Why it is important that all inhabitants of the country, also the poor and those living in remote places, have electricity available in their homes?

What is energy?

Activity 2:

To explain the term energy

[LO 2.1]

  • The activities of this module will have prepared you for answering the following questions on energy. You will have to puzzle out some of the answers and make deductions from what you have learnt. Select a partner for this activity and be sure that you and your partner make correct deductions and provide correct answers by checking with your educator.
  1. What is energy?

  1. Can energy be converted from one form to another? If you say yes, give an example.

  1. Can energy be created? If you say yes, give an example.

Assessment

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.

Memorandum

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:

  • glass container
  • filament
  • supporting wires
  • isolation glass
  • socket
  • connecting pins or screw-thread
  • contact point(s)

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.

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A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

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