Energy is the ability to do work. Everything around us — a fan spinning, food being cooked, a child running — needs energy to happen.
- Forms of Energy:
- Heat Energy: From burning fuel or friction. A stove uses heat to cook.
- Light Energy: From the Sun or electric bulbs.
- Sound Energy: From vibrating objects. A struck drum vibrates and makes sound.
- Electrical Energy: Flows through wires; powers fans, lights, and televisions.
- Mechanical Energy: Energy of moving things. A spinning top has mechanical energy.
- Chemical Energy: Stored in food and fuels; our body uses it to do work.
- Sources of Energy:
- Sun: Most important natural source. Plants use sunlight to make food (photosynthesis).
- Fossil Fuels: Coal, petroleum, natural gas — non-renewable (will run out one day).
- Renewable Sources: Solar, wind, hydro, and biogas — will not run out.
Pedalling a bicycle converts chemical energy (from food) into mechanical energy that turns the wheels.
A solar cooker converts sunlight (light energy) into heat energy — no fuel or electricity needed.
A windmill converts wind's mechanical energy into electrical energy. Many windmills together make a wind farm.
Burning wood converts chemical energy into heat and light energy, giving warmth and brightness.
Biogas from cow dung and kitchen waste is burned in villages for cooking. It is a clean, renewable source.
Common mistakes
Energy is not only electricity. Heat, light, sound, and movement are also forms of energy. Sunlight and wind are renewable; coal and petrol are non-renewable.
Summary
Energy makes everything work. It exists in many forms and converts from one to another. Prefer renewable sources like solar and wind to protect our planet.