CBSE Class 6 Science Chapter 1: The Wonderful World of Science — Important Questions

Science is a way of thinking, observing, and experimenting to understand the world around us and uncover the mysteries of the universe.

A hypothesis is a possible explanation or prediction about something that needs to be tested through experiments before it can be accepted or rejected.

Three branches of science are Physics (study of matter and energy), Chemistry (study of substances and their reactions), and Biology (study of living organisms).

The new NCERT Class 6 Science textbook is called Curiosity. It was introduced in the academic session 2024-25 as part of the new NEP-aligned curriculum.

C.V. Raman (Sir Chandrasekhara Venkata Raman) won the Nobel Prize in Physics in 1930 for discovering the Raman Effect. He was the first Asian to win a Nobel Prize in science.

Curiosity is important in science because:

• It drives scientific inquiry by making us ask questions like "why?" and "how?"
• It leads to observation, investigation, and ultimately new discoveries

Without curiosity, no scientific question would ever be asked, and no discoveries would ever be made. The NCERT textbook itself is named Curiosity to reflect this importance.

Earth is unique in the universe because:

• It is the only known planet that supports life
• It has a suitable atmosphere, liquid water, and the right temperature for living organisms to survive

Earth has diverse ecosystems with millions of species of plants, animals, and microorganisms thriving across different regions, making it a special planet for scientific study.

A scientist should repeat an experiment multiple times because:

• A single result may be due to chance or experimental error
• Repeating the experiment gives consistent and reliable results that can be trusted

Only when the same result is obtained repeatedly can a scientist draw a valid and trustworthy conclusion.

Scientists use all five sense organs for observation:

• Eyes — to see colour, shape, size, and movement
• Ears — to hear sounds and changes
• Nose — to smell substances and detect odours
• Tongue — to taste (with care and safety)
• Skin — to feel texture, temperature, and pressure

Scientific instruments like microscopes and thermometers extend the ability of our senses beyond their natural limits.

The steps of the scientific method in order are:

1. Observation — Carefully notice and record something in nature
2. Question — Ask "why" or "how" about what you observed
3. Hypothesis — Form a possible explanation or prediction
4. Experiment — Test the hypothesis by conducting a controlled experiment
5. Conclusion — Analyse results and decide whether the hypothesis was correct

Example: Observing that plants near a window grow taller → Asking why → Hypothesising that sunlight is needed → Experimenting with plants in light and dark → Concluding that plants need sunlight to grow.

Science is present in everyday life in many ways:

1. Cooking — When food is cooked, chemical reactions take place. For example, baking involves a chemical change when baking soda reacts with heat to make bread rise.
2. Weather — The changes in weather — rain, sunshine, clouds — are all natural phenomena explained by science (meteorology and atmospheric science).
3. Growing plants — Plants making their food through photosynthesis using sunlight, water, and carbon dioxide is a biological process we see around us every day.

Science is not limited to laboratories — it happens everywhere in our daily lives.

1. C.V. Raman (1888–1970)

• Discovered the Raman Effect — the scattering of light when it passes through a transparent material
• Won the Nobel Prize in Physics in 1930 — the first Asian to win a Nobel Prize in science
• His discovery is fundamental to modern spectroscopy and chemistry

2. A.P.J. Abdul Kalam (1931–2015)

• Led the development of India's first satellite launch vehicle (SLV-III) and Agni missile
• Known as the Missile Man of India for his contributions to India's space and defence programs
• Became the 11th President of India and inspired millions of students to dream big

What is Science?

Science is a systematic way of understanding the world around us through careful observation, questioning, experimentation, and analysis. It is not limited to textbooks or laboratories — science is present in every aspect of our daily lives.

Importance of Science in Human Life:

1. Health and Medicine — Science has given us vaccines, antibiotics, and surgical techniques that have saved billions of lives and increased human life expectancy. Diseases like smallpox have been completely eliminated.
2. Communication and Technology — Science led to the invention of electricity, telephones, computers, and the internet, which have transformed how humans communicate and live.
3. Agriculture and Food — Scientific discoveries in agriculture (fertilisers, irrigation, crop improvement) have helped feed the growing world population.
4. Understanding Nature — Science helps us understand natural phenomena like earthquakes, weather, and the movement of planets, allowing us to prepare and protect ourselves.

Positive Impacts:

• Development of life-saving medicines and vaccines
• Technological advances improving quality of life

Negative Impact:

• Scientific knowledge has been misused to create nuclear weapons and polluting industries causing environmental damage

Conclusion: Science is a powerful tool. Its impact on society — positive or negative — depends entirely on how humans choose to use this knowledge. Used wisely, science can solve the world's greatest problems.

The Scientific Method:

The scientific method is a step-by-step approach used by scientists to investigate questions and solve problems.

Example — Does sunlight affect plant growth?

1. Observe: Plants near a window appear taller and healthier than those in dark corners
2. Question: Does sunlight help plants grow better?
3. Hypothesis: Plants grow better in sunlight than in darkness
4. Experiment: Place two identical plants — one in sunlight, one in darkness — water them equally for two weeks
5. Conclusion: The plant in sunlight grew tall and green; the plant in darkness grew weak and pale → Hypothesis is correct

Importance of Accurate Recording:

• Accurate records allow scientists to analyse data and identify patterns
• They allow other scientists to verify and repeat the experiment
• Without accurate records, scientific knowledge cannot be shared or built upon

Importance of Repeating Experiments:

• A single result could be due to chance or experimental error
• Repeating gives consistent results that are reliable and trustworthy
• Multiple trials increase confidence in the conclusion

Together, accurate recording and repetition ensure that scientific knowledge is reliable, trustworthy, and can be used as a foundation for future discoveries.