2.7 To identify various forms of energy conversion

Natural sciences

Energy transfers and forces

Educator section

Memorandum

(a)

• Chemical → electrical
• Electrical → kinetic
• Kinetic →heat energy
• Heat energy →chemical

(b)

(i) Electrical energy – sound energy

(ii) Chemical energy – kinetic energy

(iii) Heat energy – electrical energy

(iv) Electrical energy – light energy / sound energy

(v) Electrical energy – heat energy

(vi) Electrical energy – sound energy

(c) Toy tractor.

• Potential energy – kinetic energy

Learner section

Content

Activity: to identify various forms of energy conversion [lo 2.3, lo 2.4]

Conversion of energy in motorcar engines

(a) Chemical energy is converted to electrical energy in the battery of a car. In the engine, the electrical energy is converted to kinetic energy (movement energy). When the engine overheats, the kinetic energy is converted to heat energy and when the engine cools down again, the heat energy is converted to chemical energy.

Identify the various energy transfers by underlining.

(b) Examine the illustrations that follow and indicate what kind of energy conversion has taken place.

(i)

(ii)

(iii)

(iv)

(v

(vi)

(i) _________________________________________________________________

(ii) _________________________________________________________________

(iii) _________________________________________________________________

(iv) _________________________________________________________________

(v) _________________________________________________________________

(vi) _________________________________________________________________

(c) Having fun with energy conversion

Making your own toy “tractor”.

REQUIREMENTS:

• Empty cotton reel
• Rubber band
• 2 toothpicks
• Candle wax disk cut from a round candle, with a hole in the middle

METHOD:

1. Thread the rubber band through the hole in the cotton reel.

2. Secure the rubber band in the hole by inserting half a toothpick through the loop of the protruding rubber band.

3. Place the candle wax disk against the opposite end of the cotton reel, threading the rubber through the hole in the wax disk.

4. Insert the remaining toothpick into the second loop of the rubber band.

5. Wind the “tractor” by turning the second toothpick to twist the rubber band.

6. Hold the toothpick to prevent the band from unwinding and place the reel on the ground.

7. What kind of energy conversion is illustrated?

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7. Energy issues

The utilisation of energy sources causes serious damage to our planet. We looked at the advantages and disadvantages of fossil and non-fossil fuels earlier in the module. One of the disadvantages of nuclear fuels is that radioactive waste material cannot be destroyed. A leakage of radioactive material would have disastrous results.

Some countries do not have oil (a fossil fuel) and have to buy oil from oil producing countries. This has to be transported in large oil tankers. These tankers frequently cause extensive oil slicks when they run aground along coastlines.

Assessment

Learning Outcome 2: The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

Assessment Standard 2.3: We know this when the learner interprets information by identifying key ideas in text, finding patterns in recorded data, and making inferences from information in various forms (e.g. pictures, diagrams, text);

Assessment Standard 2.4: We know this when the learner application of knowledge: applies knowledge appropriately by connecting the learnt concept to a variation of the known situation.