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Class 5 The World Around Us

Chapter 7 Solutions — Energy — How Things Work

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Solutions

Overview

Step-by-step NCERT solutions for Energy — How Things Work (Chapter 7, NCERT Class 5 The World Around Us) — every question and answer worked out in full, not just the final result. You can also read the Energy — How Things Work textbook chapter.

Solved

What these solutions cover

All 27 questions in Energy — How Things Work are solved in the PDF. Here's what's inside, exercise by exercise:

Observe and Wonder (kitchen observations)

  1. Look at a kitchen. Write one thing you observe and one question that comes to your mind.

Discuss

  1. From your observations, write down at least three things you have noticed that move, provide light, make a sound, make things hot, make things cool.

Activity 1 — Balloon (observation question)

  1. When you release the mouth of a filled balloon, what happens?
  2. What would you change in the balloon air rocket activity to make the toy move faster or slower?

Activity 2 — Rubber Band Guitar (observation question)

  1. What happens if you use thinner or thicker rubber bands in the rubber band guitar? Do they sound different?

Activity 3 — Sun-powered Water Warmer (observation question)

  1. You place one cup of water in sunlight and another in shade. After 15–20 minutes, what do you notice when you touch the water in both cups?

Discuss — Fuel for cooking

  1. What kind of fuel do you use at home for cooking?
  2. What are the problems of using too much wood or coal?

Activity 4 — Understanding How Fuel Works (diya observation)

  1. Which diya burns longer — the one with only a wick, or the one with a wick and oil? Why?
  2. What is acting as a fuel in the diya activity?

Write — How food is cooked at home

  1. How is food cooked in your house?

Activity 5 — Electricity table (devices at home)

  1. Walk around your home or classroom. Identify five things that run on electricity. Fill in the table with the device, what it does, and what it requires (light/sound/heat/movement/cooling/other).

Think — Life without electricity

  1. What would your day be like if there was no electricity at all?

Think — Cloth drying in sun vs shade

  1. You place a small damp cloth in the Sun and another in the shade. Which one do you think will dry first? Why?

Activity 6 — Pinwheel (observation question)

  1. You make a pinwheel and hold it in the wind (or run with it). What happens to your pinwheel?

Activity 7 — Sunlight in Focus (observation question)

  1. You hold a magnifying glass in sunlight and focus the light onto a piece of paper. What happens to the paper?

Activity 8 — Water Wheel (observation question)

  1. You pour water onto the paper cup water wheel. Does the water make the wheel move?

Write

  1. Can you think of more examples where we use the Sun, the wind or the flowing water in daily life?

Write — Energy All Around Us (picture table activity)

  1. Look at the picture showing various activities. List the actions you see and fill in the table: Activity and Source of Energy. One example is given: A child carrying a school bag — Food.

Activity 9 — Energy Flow Game (guidance)

  1. How do you play the Energy Flow Game? Give one example of an energy chain.

Let us reflect — End-of-chapter questions

  1. What will happen if there is no electricity in your house for a day?
  2. Why is it better to use solar or wind energy instead of coal?
  3. Give two examples where you have seen energy being stored.
  4. What is the one thing you can do at home to save energy?
  5. Find out how many kilometres a vehicle travels per litre of petrol or diesel. Ask about different vehicles. How will you compare them?
  6. Look around your home or classroom. List any three objects that use energy and mention their source of energy. (Example: Fan → Electricity)
  7. Draw or make a simple plan of a 'clean energy home' that uses solar, wind or any such source of energy. (b) Make 'my energy diary' for one day — record the number of times you have used electricity, fuel, and so on.
Sample

Worked examples

3 questions from Energy — How Things Work, solved step by step.

Discuss

From your observations, write down at least three things you have noticed that move, provide light, make a sound, make things hot, make things cool.

Things that move: leaves blowing in the wind, a flying bird, a flowing river.

Things that provide light: the Sun, a lit bulb, a flame.

Things that make a sound: thunder, a ringing bell, a barking dog.

Things that make things hot: the Sun, fire, a heater.

Things that make things cool: a fan, wind, cold water.

Answer: Moving: leaves, birds, river. Light: Sun, bulb, flame. Sound: thunder, bell, dog. Hot: Sun, fire. Cool: fan, wind. (Your own examples will vary.)

Activity 1 — Balloon (observation question)

When you release the mouth of a filled balloon, what happens?

When air rushes out of the balloon, it pushes the balloon forward.

The movement of air generates energy that makes the balloon move.

Answer: The balloon moves forward because the air rushing out pushes it in the opposite direction.

Activity 2 — Rubber Band Guitar (observation question)

What happens if you use thinner or thicker rubber bands in the rubber band guitar? Do they sound different?

Thinner rubber bands vibrate faster and produce a higher-pitched sound.

Thicker rubber bands vibrate more slowly and produce a lower-pitched, deeper sound.

Yes, they sound different — thin bands make a sharper sound and thick bands make a deeper sound.

Answer: Yes, they sound different. Thinner bands make a higher sound; thicker bands make a lower, deeper sound.

All 27 questions in Energy — How Things Work are solved step by step in the Solutions PDF above.

Keep solving

More solutions in Our Wondrous World

01Water — The Essence of Life02Journey of a River03The Mystery of Food04Our School — A Happy Place05Our Vibrant Country06Some Unique Places08Clothes — How Things are Made09Rhythms of Nature10Earth — Our Shared Home
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More NCERT Solutions for Class 5

Read the Energy — How Things Work textbook chapter / PDF, or browse all NCERT Class 5 The World Around Us solutions.

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