☰ خطة العام · العلوم (بالإنجليزية)

Fossil fuels, electricity and pollution

الأسبوع 19 · المحور الثالث، الوحدة الثالثة، المفهوم 3.2 «الوقود وأنواعه» (ب): الوقود الأحفوري والتلوث وترشيد الاستهلاك · 3 دروس
2

From fuel to the light in our home

Discovery Education Science P4: Term 2, Unit 3, pp. 40–55
GoalDescribe how a power plant uses a fuel to make electricity, and reflect on a short time without electricity.
New words
turbine · a wheel with blades that is turned by steam, water or windgenerator · a machine that changes motion into electrical energypower line · a cable that carries electricity to homes
Explanation

A lot of the electricity that lights our homes is made in a power plant. The steps are these. A fuel such as natural gas, coal or oil is burned. The burning fuel gives thermal energy, which heats water until it becomes steam. The steam is pushed through pipes at a turbine and makes it spin. The spinning turbine turns a generator, which changes motion into electrical energy. Then power lines carry the electricity to homes, schools and shops. What would it be like without it? A few hours without electricity makes us notice how much we use. In daylight, and with a grown-up in charge, we can try: no lamps, no screens, no plug-in toys. We can read by the window, play board games, draw or help cook. We never use candles or matches for this game.

Worked examples
Karim’s family has a “quiet afternoon”. From 1:00 to 4:00, with Dad in charge, nobody uses a screen or a plug-in toy. They read, draw and play cards. The time without electricity is 4 − 1 = 3 hours.
In a power plant using natural gas, the gas burns and heats water to steam. Steam turns the turbine and the generator makes electricity. The chain: chemical, then thermal, then motion, then electrical.
power planthomelamp
Electricity travels from the plant along power lines on tall pylons and then into the wires inside a home, to the lamp. A grown-up deals with all wires and sockets.
Class activity

Quiet afternoon. A grown-up chooses a daylight time of two to three hours with no screens, no plug-in toys and no lamps. No candles or matches. Do things like reading, drawing or board games. Then write: What did you do instead? What was easy? What was hard? Which devices do you usually take for granted? How can you save electricity?

Practice
1
Put the power-plant steps in order. A: the turbine spins. B: the fuel burns. C: steam is made. D: the generator makes electricity. Say the letters.
2
What does a generator change?
3
A family has no electricity from 10:00 in the morning to 1:00 in the afternoon. For how many hours?
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4
Name two things you can do instead of using a screen in a quiet afternoon.