CBSE Class 7 Science Chapter 1: The Ever Evolving World of Science — Assertion & Reason
CBSE Class 7 Science Assertion & Reason
Expert crafted · Instant PDF download · 2026-27
The following Assertion and Reason questions are based on Chapter 1: The Ever-Evolving World of Science from the NCERT Class 7 Science textbook Curiosity. Each question has four options — read both the Assertion (A) and Reason (R) carefully before selecting your answer.
How to attempt Assertion & Reason questions:
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Assertion & Reason Questions
1
Assertion (A): Science is only about memorising facts discovered by others from a textbook.
Reason (R): Science is a process and a way of thinking that welcomes curiosity, asks questions, and is open to the unknown.
Reason (R): Science is a process and a way of thinking that welcomes curiosity, asks questions, and is open to the unknown.
Answer: (d)
A is false, but R is true. Science is not just a collection of facts; it is an ongoing process of exploration, asking how things work, and conducting experiments.
2
Assertion (A): Something as simple as a paper plane can inspire real scientific explorations.
Reason (R): Early inventors studied bird wings and simple flying objects, which eventually led modern engineers to design aircraft.
Reason (R): Early inventors studied bird wings and simple flying objects, which eventually led modern engineers to design aircraft.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The dream of flying started with simple observations and experiments, proving that small curiosities can lead to major scientific breakthroughs.
3
Assertion (A): Scientific discoveries in one area, such as physics, are completely isolated from other areas like biology.
Reason (R): Scientific ideas in one area often inspire discoveries or allow us to ask new questions in another area.
Reason (R): Scientific ideas in one area often inspire discoveries or allow us to ask new questions in another area.
Answer: (d)
A is false, but R is true. All fields of science are interconnected, and a discovery in one field frequently influences and builds upon another.
4
Assertion (A): Science plays an important role in addressing global environmental challenges.
Reason (R): Understanding how human activities are linked to the natural world helps us create a more sustainable planet.
Reason (R): Understanding how human activities are linked to the natural world helps us create a more sustainable planet.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. By studying science, we learn how our actions affect the environment, equipping us to find sustainable solutions for the future.
5
Assertion (A): Asking why some fruits are sour is a valid scientific inquiry.
Reason (R): The taste of a fruit is related to the specific properties of the materials it is made of.
Reason (R): The taste of a fruit is related to the specific properties of the materials it is made of.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Questioning everyday experiences, like the sourness of a fruit or removing a haldi stain, helps us explore the chemical properties of materials.
6
Assertion (A): To make an electric lamp glow, we only need a battery and a lamp without any connecting wires.
Reason (R): We need specific kinds of materials, such as conducting wires, to complete an electric circuit.
Reason (R): We need specific kinds of materials, such as conducting wires, to complete an electric circuit.
Answer: (d)
A is false, but R is true. A complete path made of conducting materials (wires) is necessary to connect the battery to the lamp and make it glow.
7
Assertion (A): Playing with batteries, lamps, and wires helps us classify materials as metals and non-metals.
Reason (R): By testing which materials allow the lamp to glow, we can determine which materials conduct electricity (metals) and which do not (non-metals).
Reason (R): By testing which materials allow the lamp to glow, we can determine which materials conduct electricity (metals) and which do not (non-metals).
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Setting up electrical circuits is a practical way to explore the conducting properties of different materials.
8
Assertion (A): All physical and chemical changes that happen around us can be reversed.
Reason (R): The melting of an ice cube is a change that can be reversed, but a battery running out is a change that cannot be easily reversed.
Reason (R): The melting of an ice cube is a change that can be reversed, but a battery running out is a change that cannot be easily reversed.
Answer: (d)
A is false, but R is true. Not all changes are reversible. While melting ice can be frozen again, a depleted battery or a ripened fruit cannot return to its original state.
9
Assertion (A): The flow of heat is responsible for both the melting of an ice cube in a glass and the melting of a massive glacier.
Reason (R): Heat energy causes certain materials like ice to change their state from solid to liquid.
Reason (R): Heat energy causes certain materials like ice to change their state from solid to liquid.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Regardless of the scale, the scientific principle of heat flow causing a change of state remains the same.
10
Assertion (A): Heat from the Sun causes water to evaporate from the seas and oceans.
Reason (R): Evaporated water eventually condenses and falls back down to the ground as rain.
Reason (R): Evaporated water eventually condenses and falls back down to the ground as rain.
Answer: (b)
Both A and R are true, but R is NOT the correct explanation of A. Both statements correctly describe steps in the water cycle, but the fact that it rains later does not explain why the Sun's heat causes evaporation.
11
Assertion (A): The circulatory system is essential for the growth and survival of animals.
Reason (R): Blood circulates the necessary nutrients obtained from food all over the body.
Reason (R): Blood circulates the necessary nutrients obtained from food all over the body.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Animals undergo rapid changes and growth, which requires nutrients to be transported efficiently throughout the body by the blood.
12
Assertion (A): Plants do not need to take in food or breathe because they remain fixed in one place.
Reason (R): Just like animals, plants also have life processes and require nourishment and gas exchange to grow and survive.
Reason (R): Just like animals, plants also have life processes and require nourishment and gas exchange to grow and survive.
Answer: (d)
A is false, but R is true. Plants are living organisms. Even though they do not move around like animals, they still must produce food and breathe to maintain their life processes.
13
Assertion (A): Early humans used the shadows of objects cast by the Sun to tell the time.
Reason (R): Before the invention of electric clocks and watches, the changing position and length of shadows helped track the passing of the day.
Reason (R): Before the invention of electric clocks and watches, the changing position and length of shadows helped track the passing of the day.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. As the Sun appears to move across the sky, the predictable changes in shadows provided a natural clock for early humans.
14
Assertion (A): Light is only useful for creating shadow puppets and telling the time during the day.
Reason (R): Light helps us see the world around us, and modern science has developed various ways to generate artificial light for use at night.
Reason (R): Light helps us see the world around us, and modern science has developed various ways to generate artificial light for use at night.
Answer: (d)
A is false, but R is true. Light's primary importance is that it enables vision. Its applications go far beyond shadow puppets, including the modern necessity of artificial lighting.
15
Assertion (A): The fascinating phenomena of eclipses occur because celestial bodies like the Earth and the Moon can cast shadows.
Reason (R): Eclipses happen when a massive object blocks the light from the Sun, casting a large shadow onto another object in space.
Reason (R): Eclipses happen when a massive object blocks the light from the Sun, casting a large shadow onto another object in space.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Eclipses are simply large-scale shadow events that occur due to the alignment of the Sun, Earth, and Moon.
16
Assertion (A): The cycle of day and night on Earth is entirely dependent on receiving light from the Sun.
Reason (R): The Earth continuously rotates around its own axis, causing different parts of the planet to face the Sun at different times.
Reason (R): The Earth continuously rotates around its own axis, causing different parts of the planet to face the Sun at different times.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The rotation of the Earth is the mechanical reason why the Sun's light creates alternating periods of day and night across the globe.
17
Assertion (A): The Earth remains completely stationary in space while the Sun and the Moon revolve around it.
Reason (R): The Earth rotates on its axis and revolves around the Sun, while the Moon revolves around the Earth.
Reason (R): The Earth rotates on its axis and revolves around the Sun, while the Moon revolves around the Earth.
Answer: (d)
A is false, but R is true. The Earth is in constant motion, both rotating on its axis and orbiting the Sun, contrary to ancient beliefs.
18
Assertion (A): In the process of science, asking amazing and interesting questions is just as important as finding the answers.
Reason (R): The most groundbreaking discoveries in science often begin with a simple question like "Why?".
Reason (R): The most groundbreaking discoveries in science often begin with a simple question like "Why?".
Answer: (a)
Both A and R are true, and R is the correct explanation of A. True scientific exploration is driven by curiosity. Without asking questions, there would be no new discoveries to make.
19
Assertion (A): Scientific experiments always perfectly confirm what we expect will happen without raising any new questions.
Reason (R): Scientific experiments often lead to unexpected observations that require more questions and further experiments.
Reason (R): Scientific experiments often lead to unexpected observations that require more questions and further experiments.
Answer: (d)
A is false, but R is true. Science is an ever-evolving journey. Answering one question through an experiment frequently uncovers new mysteries that need to be explored.
20
Assertion (A): To be a successful scientist, one must only memorise the textbook answers given by teachers.
Reason (R): A scientist observes the world, asks creative questions, performs hands-on experiments, and is open to exploring the unknown.
Reason (R): A scientist observes the world, asks creative questions, performs hands-on experiments, and is open to exploring the unknown.
Answer: (d)
A is false, but R is true. Memorisation is not the core of science. Science is an active process of inquiry, imagination, and practical experimentation.
❓ Frequently Asked Questions
What is covered in CBSE Class 7 Science Chapter 1 The Ever Evolving World of Science?
This chapter covers all key topics from The Ever Evolving World of Science as per CBSE 2026-27 syllabus.
Is this Assertion & Reason useful for CBSE board exams?
Yes, designed for CBSE Class 7 board exam preparation covering the complete syllabus.
Are these CBSE Class 7 Science Assertion & Reason updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 7 Science?
All chapters of CBSE Class 7 Science are covered at eBookPublisher with free Assertion & Reason for each chapter.
Can I study The Ever Evolving World of Science online for free?
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