Page 79 - ScienceStd4

as lightning and stars including the sun. It can also come from
non-natural sources like firewood, charcoal, coal, electricity,
oil, friction and gas. These sources are used to produce heat
for various daily applications. Examine Figure 1, then read the
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explanations that follow.

(a) Sun (b) Firewood stove (c) Charcoal

(d) Electric cooker (e) Gas cooker

Figure 1: Sources of heat energy

Figure 1(a) shows the sun, which is the primary natural source of
heat energy. Figure 1(b) and 1(c) show cooking activities using

firewood and charcoal as sources of heat. Figure 1(d) and 1(e)
show cooking activities using electricity and gas respectively.

Activity 1

Identifying a source of heat

Materials: One dry stick and a piece of dry wood

Procedure

1. Rub your palms together.

2. Write down what you feel while rubbing your palms.

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SCIENCE AND TECHNOLOGY STD 4.indd 72
SCIENCE AND TECHNOLOGY STD 4.indd 72 14/01/2025 18:38