NCERT Solutions for Class 6 Science Chapter 1 the Wonderful World of Science (PDF) – 2027

Yes. In the Preparatory Stage (Classes 3 to 5) I enjoyed finding things out for myself — watching leaves, ants and the changing shape of the Moon, collecting seeds and pebbles, growing gram seeds on wet cotton, and asking elders about their childhood. Discovering things was far more fun than memorising them.

Science is a way of thinking, observing and doing things to understand the world we live in and to uncover the secrets of the universe. It is like a big adventure — we ask questions, explore the world and try to understand how things work. The most important thing for this is curiosity.

Yes. Stars shine because each star makes its own light and heat. Our Sun is also a star — the nearest one. The other stars look like tiny points of light only because they are very, very far away. They seem to twinkle because their light passes through the moving layers of air around the Earth.

Yes. A flower “knows” when to open because the plant can sense changes in its surroundings — light and darkness, and the rise and fall of temperature between day and night. Plants also have an inner body clock. So a lotus opens in the morning, while raat ki rani blooms at night. Responding to the surroundings is a sign of living things.

We will start with our home, planet Earth, and then go beyond it. We will explore the Earth and its environment; the variety of plants and animals and how they grow; food and what it is made of; water, rain, ice and steam; hot and cold; materials and how to separate them; the structure of a leaf and how things move; and the Sun, the Moon and the stars. We will also find that all these ideas are connected.

Plants and animals grow by taking in food and using it to build new parts of the body. Green plants make their own food in their leaves using sunlight, water and air; animals eat plants or other animals. A seed grows into a young plant, a caterpillar changes into a butterfly, and a calf grows into a cow. Most animals stop growing when they become adults, but many plants keep growing all their life.

However different they look, our dishes are made of a few main food components — carbohydrates, proteins, fats, vitamins and minerals — along with dietary fibre and water. We find out which components a food contains by testing it. For example, a drop of iodine solution turns starchy food blue-black, and food that leaves an oily patch on paper contains fat.

Yes. Rain is part of the water cycle. The Sun’s heat changes water from seas, rivers and lakes into invisible water vapour (evaporation). The vapour rises, cools high up and turns into tiny droplets, which together form clouds (condensation). When the droplets join and become too heavy, they fall as rain. The water flows back to the sea and the cycle goes on.

Yes. When water is cooled to 0 °C it freezes and becomes ice (a solid). When it is heated to 100 °C it boils and becomes steam (a gas). Ice melts back into water when warmed. It is the same water in every form — only its state changes.

Yes. By touch we can only tell whether something feels hotter or colder than our hand, and touch can easily be fooled. To know exactly how hot something is, we measure its temperature with a thermometer, in degrees Celsius (°C). For example, normal body temperature is about 37 °C; a higher reading means fever.

Yes, they are made of different materials, each chosen to suit its job: paper from wood pulp, the key from metal, the ruler from plastic, the eraser from rubber, clothes from cotton, wool or other fibres, and the cup from glass, steel or clay. We separate materials by using a property in which they differ — for example by handpicking, winnowing, sieving, using a magnet, filtering or evaporating.

By following the scientific method. We observe something, ask a clear question about it, guess a possible answer, test the guess by experiments or more observations, and analyse the result. If the guess turns out to be wrong, we make a new guess and test again. We can also read, ask our teacher and discuss with friends.

I would ask myself, “Why did my pen stop writing?” I might guess that the ink has finished. I would test this guess by opening the pen and checking the ink refill. If the refill is empty, I would know that my guess was correct.

Then my first guess was wrong, so I would make another guess and test it. For example, perhaps the ink has dried up at the tip. To test this, I would scribble hard on rough paper or dip the tip in a little warm water. If the pen starts writing, this guess was correct; if not, I would make a new guess (such as a stuck ball at the tip) and test that too.

One morning my bicycle became very hard to pedal, though nothing looked broken. I first guessed that the chain had become dry, but it was oiled and moved freely, so that guess was wrong. Next I guessed that the rear tyre had less air. I pressed both tyres: the rear one sank in easily. After I filled air in it, the cycle ran smoothly. My second guess was correct.

Sample answer (for the bicycle problem): I followed the steps of the scientific method — I observed the problem, asked why it happened, made two guesses, tested each one, and analysed the result.

The steps of the scientific method are:

1. First, we observe something that we find interesting or we do not understand.
2. This makes us wonder and perhaps think of a question about it.
3. Then, we guess a possible answer to that question.
4. We test this guess through experiments or more observations.
5. We then try to analyse the results to see if it actually answers our question.

Yes. We often use the scientific method without knowing it. A cook wonders why the dal spilled out of the cooker — was there too much water? A bicycle repairer finds out where the air leaked from a flat tyre. An electrician checks whether the fault is in the bulb or the switch. When we ask questions and find out answers, we are all, in a way, scientists.

Our ceiling fan started making a loud noise. My father guessed that a blade had become loose, but when he checked, all three blades were tight — so that guess was wrong. He then guessed that dust and grease on the blades were unbalancing the fan. He cleaned the blades and switched the fan on: the noise had stopped. He observed, guessed, tested and analysed — he followed the scientific method.

I would ask, “Why does a cut apple turn brown when it is left on the plate?” I have seen this every time an apple is cut: the brown colour appears only on the cut surface, not on the skin.

Sample answer (for the apple question): I would guess that the air makes the cut surface turn brown. To test this, I would cut an apple into pieces, leave one piece open on a plate, wrap one tightly in cling film and keep one under water. After about an hour I would compare them. If the open piece is the brownest, the air is the cause.

This line is a play on words: “wise” and “whys” sound almost the same. It means that to become wise, we must keep asking “why?” about things around us and then honestly look for the answers. Wisdom comes from understanding the reasons behind things, not from memorising ready-made answers.

Yes! I am ready. I will stay curious, observe my surroundings keenly, keep asking “how?” and “why?”, test my guesses using the scientific method, and ask my friends for help when I am stuck. I will not find every answer in Grade 6, but the journey will go on for the next five years and beyond.