Class 5 EVS Chapter 7 – “Energy: How Things Work”- Complete Notes and Concept-wise Summary (Paragraph-wise Explanation)
All concepts are simplified for students, with clear explanations of key ideas and textbook “Do You Know?” Important Points also given.
Chapter 7 – Energy: How Things Work
Concept-wise Notes & Summary
1. What is Energy?
Energy is the power that makes things move, shine, make sound, or change temperature.
In our daily life, energy helps in many activities like:
- Moving a fan (movement energy)
- Lighting a bulb (light energy)
- Cooking food (heat energy)
- Listening to music (sound energy)
- Running machines (mechanical energy)
Example:
In a kitchen, when food is cooked, energy is used in the form of heat.
Do You Know?
The Flying Snake found in Indian forests can glide through the air by flattening its body—showing how living beings also use energy to move!
2. Understanding Energy through Activities
Activity 1: The Balloon and Air Rocket
When you release a blown-up balloon, the air rushing out pushes it forward.
This shows movement through air energy.
Extension:
Attaching a balloon to a straw and string creates a balloon rocket.
- More air = Faster movement
- Less air = Slower movement
Concept: Air movement carries energy that can move objects.
Activity 2: Rubber Band Sound
When you stretch and pluck a rubber band, it vibrates and makes a sound.
This vibration produces sound energy.
Observation:
- Thicker bands produce deeper sounds.
- Thinner bands make higher sounds.
Do You Know?
The Bhadla Solar Park in Rajasthan is one of the world’s largest solar power plants — showing how we use sunlight as an energy source.
Activity 3: Sun-powered Water Warmer
When two cups of water are placed — one in sunlight and one in shade —
the one in sunlight becomes warm.
This shows that sunlight provides heat energy.
Do You Know?
In Himachal Pradesh, Uttarakhand, and Ladakh, people keep cattle on the ground floor during winter. The animals’ body heat helps keep rooms above warm naturally — a smart traditional energy-saving practice.
3. Sources of Energy
Every living thing needs energy to move, grow, and stay active.
- Humans and animals get energy from food.
- Vehicles get energy from fuels.
- Machines and appliances use electricity.
When we eat food, our body gets energy to play, run, and think.
When we skip meals, we feel tired because our energy levels drop.
Do You Know?
Even when we sleep or think, our brain still uses energy.
4. Energy from Fuel
Vehicles like cars, buses, and scooters use petrol or diesel to move.
These fuels provide energy just as food does for us.
At home, we use:
- LPG (cooking gas) for stoves,
- Wood or coal in some areas for cooking.
Problem:
Burning too much wood or coal creates smoke and pollution, so we must use fuel carefully.
Do You Know?
Cochin International Airport (Kerala) is the first airport in the world to run entirely on solar power — clean energy!
Activity 4: Understanding How Fuel Works
- When two diyas are lit — one with oil and one without —
the one with oil burns longer.
The oil acts as fuel.
This shows that fuel helps fire burn and produce light and heat energy.
Do You Know?
Traditional Indian homes with thick walls and small windows stay cool in summer and warm in winter — a natural energy-efficient design!
5. Electricity
Electricity is an important source of energy in our lives.
It helps in:
- Lighting bulbs,
- Running fans and machines,
- Heating water,
- Cooling rooms with ACs or refrigerators.
Activity 5: Devices Running on Electricity
| S. No. | Device | What It Does | Energy Type |
|---|---|---|---|
| 1 | Fan | Blows air | Movement |
| 2 | Bulb | Gives light | Light |
| 3 | Television | Plays sound and image | Sound & Light |
| 4 | Refrigerator | Keeps food cool | Cooling |
| 5 | Iron | Presses clothes | Heat |
Concept:
Electricity provides light, heat, movement, and sound.
Do You Know?
Energy efficiency means using less energy to do the same work — e.g., LED bulbs save electricity.
6. Safe Use of Electricity
Electricity must be used carefully. Follow these rules:
- Don’t touch wires or sockets.
- Don’t insert objects into plug points.
- Stay away from broken wires or poles.
- Don’t play near transformers.
- Always inform an adult if something looks unsafe.
Most electricity comes from burning coal, which pollutes air.
That’s why we must use clean energy sources like wind, water, and sunlight.
Do You Know?
In hilly regions, watermills (gharaats) use flowing water to grind grains — a natural energy method!
7. Generating Energy from the Sun, Wind, and Water
These are renewable sources — they don’t get used up and don’t pollute the Earth.
Activity 6: Pinwheel
When wind blows, the pinwheel spins — showing wind energy.
Activity 7: Sunlight in Focus
When sunlight is focused on paper using a magnifying glass, it can burn — showing solar energy.
Activity 8: Water Wheel
When water is poured on a wheel with spoons, it turns — showing water energy.
Do You Know?
Ancient ships used wind energy in their sails to travel long distances for trade!
Concept Summary:
- Sun → Heat & Light energy
- Wind → Movement energy
- Water → Movement energy
Do You Know?
The Sun is the main source of energy for all life on Earth.
8. Clean and Renewable Energy
Solar panels convert sunlight into electricity.
Windmills spin to create electricity.
Flowing water turns turbines in dams to make power.
This electricity is called clean energy because it does not create smoke or waste.
Do You Know?
The Sun gives more energy to Earth in one hour than all humans use in a whole year!
9. Energy All Around Us
| Activity | Source of Energy |
|---|---|
| A child carrying a bag | Food |
| A car moving | Fuel |
| A fan spinning | Electricity |
| Clothes drying | Sunlight |
| Windmill turning | Wind |
Do You Know?
Batteries store energy for later use — like our body stores energy from food!
10. Energy Flow Game (Activity 9)
A fun game to learn how energy moves from source → type → use.
Example:
- Sun → Heat → Dries clothes
- Wind → Movement → Turns turbines
- Water → Movement → Spins water wheel
Learning:
Energy flows from one form to another and is used to make things work.
11. Vaastu and Natural Energy
Vaastu Shastra, the ancient Indian design system, guides building placement to use sunlight and wind effectively.
It helps homes stay bright, airy, and energy-efficient.
Do You Know?
Some desert plants open only at night to save water and energy — showing how nature is smart with energy use.
12. Importance of Saving Energy
Energy keeps our world active and alive.
We must use energy wisely and prefer clean energy sources like:
- Solar power
- Wind energy
- Hydropower
Simple Ways to Save Energy:
- Turn off lights when not needed.
- Use public transport or cycles.
- Dry clothes in sunlight.
- Switch to LED bulbs.
- Use solar cookers and panels.
Energy is all around us — in the food we eat, the fuel we use, and the Sun that lights our day.
By choosing clean, renewable energy and using it carefully, we can protect our planet and ensure a bright, healthy future.
Other Important Notes Related to This Chapter
NCERT Question Answer Solution Class 5 chapter 7 – Energy: How Things Work
CBSE Summary Notes Chapter 7 – Energy: How Things Work
Extra Questions Chapter 7 – Energy: How Things Work
Practice Worksheet Chapter 7 – Energy: How Things Work