الأسبوع 13 · الموضوع ٢-٤ «الغلاف الجوي ودور العلم في استدامته» (١): الاحتباس الحراري والغازات الدفيئة وطرق خفض الانبعاثات وملوثات الهواء وتكوين الأمطار الحمضية · 3 دروس
2
Cutting emissions: what helps and why
Integrated Science Sec 1 Term 1, Unit 2: pp. 98–102
GoalExplain which actions cut greenhouse gas emissions, and why each works.
New words
emission · a gas released into the airrenewable energy · energy from sources that do not run out, like sun, wind and flowing waterafforestation · planting trees where there were none
Explanation
Fewer emissions mean fewer extra greenhouse gases. Ways to cut them: use public transport and share journeys, so fewer fuel engines run; use energy-efficient appliances and LED lamps, which need less electricity and so less fuel at power stations; use clean renewable energy (solar, wind, hydropower), which release no CO₂ when they work; and plant trees (afforestation), because photosynthesis takes CO₂ from the air. Each action either burns less fuel or takes CO₂ back from the air. Small actions of many people add up, and no blame is needed to start. Safety in the home: never run an engine or burn fuel or charcoal in a closed room; if a gas heater smells wrong, tell an adult and open a window. Do not try any experiment with burning, exhaust or smoke.
Worked examples
Compare lamps. An old lamp uses 60 W and a new LED uses 9 W. The new one uses 9 ÷ 60 × 100 = 15% of the power. For five lamps the saving is 5 × (60 − 9) = 255 W.
Match each action to its way of working. Public transport: less fuel burned. LED lamps: less electricity needed. Solar power: no CO₂ while working. Planting trees: CO₂ taken in by photosynthesis.
A class of 30 pupils plans to walk to school on one extra day each week. If this replaces a 10-minute drive for 6 pupils, the class makes 6 fewer car trips a week. Small steps, repeated, reduce fuel use.
Class activity
Sorting game with cards. Write 12 cards: six sources (power station, bus, burning gas, forest, solar panel, wind turbine) and six actions. Sort them into: adds CO₂, removes CO₂, adds none while working. Then choose three actions your family could do and write why each helps. Plant a few seeds in a cup of soil as the afforestation idea and water them.
Practice
1
Why does planting trees help cut CO₂ in the air?
Photosynthesis takes CO₂ from the air.
2
A 12 W lamp replaces a 60 W lamp. What share of the power does it use?
12 ÷ 60 × 100 = 20%.
3
Name two clean renewable energy sources.
For example: solar and wind (or hydropower).
4
Why must engines and heaters never run in a closed room?
They can build up harmful gases, so open a window and tell an adult.
