Energy and Saving It
FoundationEnergy from sun, water and wind never runs out, but coal, oil and gas will. Power generation and daily life everywhere need energy — saving starts with switching off lights.
- Two kinds of energy: solar, water and wind never run out; fossil fuels will.
- Transport, manufacturing, lighting and electronic devices all need energy.
- Hong Kong generates power mainly from coal and natural gas, which pollute.
文體小知識：說明文把能源的來源和節約方法講得井井有條。這一篇教你認識電從哪裏來，再學做個精明的慳電小管家。
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1Switching on lights, riding buses, playing on a tablet — all need energy. Energy is a resource that gives us power, like food for the body; without it, buses stop, lights go out, factories halt, and life falls into chaos. Energy hides in coal, oil and natural gas, and also in sunshine, flowing water and wind.
2Energy falls into two kinds by whether it runs out. Solar, water and wind energy come from nature's endless cycles — sunshine shines daily, rivers keep flowing, wind never rests — so they will not run out. Coal, oil and natural gas formed from the remains of plants and animals billions of years ago, buried underground; the more we use, the less remains, and one day they will be gone. These are called non-renewable energy, or fossil fuels.
3Hong Kong has no oilfields or great rivers, so its electricity is made mainly by burning coal and natural gas, with a small share from waste-to-energy. Power stations burn fossil fuels to make heat that drives generators, and cables carry electricity to every home. Burning fossil fuels releases carbon dioxide and air pollutants, worsening air quality and climate change — so saving energy matters even more in Hong Kong.
4Daily life needs energy everywhere: buses, MTR trains and planes burn fuel or use power; factories use great energy to make toys and clothes; roads and buildings need electricity for lighting at night; phones and computers charge every day. Imagine a citywide blackout for one hour tomorrow — how would life be hit? Then you know how precious energy is.
5Everyone can save energy: switch off lights when leaving a room, choose LED lamps, set air-conditioning around twenty-six degrees with a fan in summer, switch appliances off when unused, and ride public transport more. Every unit saved means less fuel burnt at the power station — saving money and protecting the environment. Let saving start tonight.
1Summary 重點摘要
Energy from sun, water and wind never runs out, but coal, oil and gas will. Power generation and daily life everywhere need energy — saving starts with switching off lights.
2Vocabulary cards Vocabulary
A resource that gives us usable energy, such as coal and sunshine.
Energy from the sun's light and heat; it never runs out.
Energy made when wind turns wind turbines to generate electricity.
Energy made from the power of flowing water.
A black fossil fuel buried underground; burning it makes electricity.
An oily fossil fuel from underground, refined into petrol and other products.
A gaseous fossil fuel underground; burning it for power is cleaner than coal.
The collective name for coal, oil and natural gas, formed from ancient life and running out.
Making electricity from different energy sources.
Using energy wisely and wasting less, such as switching off lights when leaving a room.
3Step by step Steps
- Step 1: What energy isAn energy source is a resource that provides usable energy. People need food for strength; machines need energy to run: cars burn petrol, lamps use electricity, water heaters burn gas — energy is at work behind them all. Count how much energy you use between waking and reaching school: kettle, lights, lift, bus, computer… you cannot finish counting. Because life cannot go on without energy, we must learn where it comes from and how to treasure it.
- Step 2: Energy that never runs outSolar, water and wind energy will never be used up. The sun rises every day, and its light turns into power and heat through solar panels; rivers flow day and night, and dams use the falling water to drive generators; wind spins huge turbine blades to make electricity too. Coming from nature's cycles, they are inexhaustible and almost pollution-free when generating — clean energy. Yet they depend on the weather: no sunshine at night, and wind turbines stand still on windless days.
- Step 3: Fossil fuels that run outCoal, oil and natural gas are together called fossil fuels, formed from the remains of plants and animals buried deep underground and changed by great heat and pressure over billions of years. Their problems are two. First, supplies are limited: the more we burn, the less remains, and one day they will be gone. Second, burning them releases carbon dioxide that speeds up climate change, along with air pollutants that harm health. Oil is also refined into petrol, aircraft fuel and plastic. The less fossil fuel we use, the more is left for the future.
- Step 4: How Hong Kong makes electricityHong Kong is small and crowded, with no oilfields, no great rivers and little land for wind farms, so its power has long come mainly from burning coal and natural gas, with a small share from waste-to-energy. Power stations heat water into high-pressure steam that drives turbines and generators, and overhead and underground cables carry electricity across the territory. In recent years solar panels have appeared and wind power is being studied. Knowing where electricity comes from, we see that every unit saved truly cuts pollution.
- Step 5: What activities need energyFour great areas of modern life lean on energy. Transport: buses, MTR trains, ferries and planes burn fuel or use power to carry us to school and far away. Manufacturing: factories run machines turning raw materials into clothes, toys and food. Lighting: lamps on streets, in malls, classrooms and homes light up the city every night. Electronic devices: phones, computers and game consoles charge daily. Energy seems as ever-present as air, but it is not free — precious resources are consumed behind it.
- Step 6: Saving energy at homeSaving energy starts with small things at home. Lighting: choose LED lamps, which use far less power than old bulbs; switch lights off when leaving a room. Air-conditioning: set it around twenty-six degrees and run a fan to move the air — cheaper than blasting the cold; keep doors and windows shut while it is on. Appliances: switch off unused ones so standby does not waste power; do not overfill the fridge or press it against the wall. Laundry: wash only full loads. These habits together show up on the electricity bill within a month.
- Step 7: Saving energy on the move and in societyWhen going out, take the MTR, buses and other public transport — far less energy than everyone in taxis or private cars; walk or cycle short trips, which is green and healthy. Schools and offices can rely on natural light and switch on fewer lamps when it is not dark. Across society, the government promotes cleaner ways of generating power and electric vehicles. Energy and climate change are global issues: each family saving a little adds up to an astonishing total for Hong Kong. Saving energy is environmental action everyone can join.
5Worked example Example
Example: Ming's family electricity bill last month was far higher than usual. Dad found that Ming switched on every big lamp while doing homework; the air-conditioner was set to twenty degrees with the window open; the TV and game console stood by all night; the washing machine ran daily with only two or three shirts. Point out the wasteful habits and give advice.
- Lighting the whole house wastes power; one desk lamp is enough for homework, and an LED lamp saves even more.
- Cooling with the window open chills the street too; close doors and windows and set the air-conditioner around twenty-six degrees.
- The TV and console on standby all night keep sipping power; switch them off when not in use.
- Running the washer daily for two or three shirts wastes water and power; wait for a full load.
- Answer: The wasteful habits are four: too many lamps, air-conditioning set too cold with the window open, appliances on standby all night, and half-empty laundry loads. The fixes: light only what is needed with LEDs, set the air-conditioner around twenty-six degrees and close windows, switch appliances off, and wash full loads — the bill will naturally fall.
6Common mistakes Mistakes
7Quick check Quick check
Q1Name three kinds of energy that never run out.
Q2What are coal, oil and natural gas called together?
Q3What does Hong Kong mainly burn to make electricity?
Q4At about what temperature is air-conditioning most economical?
Q5What should we do with appliances when not using them?
8Recap Recap
- Two kinds of energy: solar, water and wind never run out; fossil fuels will.
- Transport, manufacturing, lighting and electronic devices all need energy.
- Hong Kong generates power mainly from coal and natural gas, which pollute.
- Lights off, air-con at twenty-six, appliances switched off — saving starts small.
- Saving energy saves money and cuts pollution; it is everyone's duty.