Important Questions for Class 8 Science Chapter 1: Exploring the Investigative World of Science by PW

Practising Important Questions for Class 8 Science Chapter 1 is one of the best ways to strengthen your understanding of the chapter and prepare confidently for school exams. These questions cover all the key concepts, important definitions, diagrams, and application-based topics that are frequently asked in exams. Solving them regularly also helps improve problem-solving skills and boosts confidence.

To make your preparation easier, Physics Wallah provides a selected set of important questions along with detailed solutions prepared by subject experts. Whether you're revising before a test or completing your syllabus, these PW Important Questions for Class 8 Science Chapter 1 will help you understand the concepts better and score higher in your examinations.

Important Questions for Class 8 Science Chapter 1

These exam-oriented questions focus on the most important topics from the chapter and will help you practise, revise, and improve your confidence before your exams.

1. In an experiment to measure force, which instrument should be used?

(A) Measuring cylinder
(B) Spring balance
(C) Thermometer
(D) Magnifying glass

2. To show water vapor in air, which simple activity can be performed?

(A) Boil water and capture steam
(B) Put cold water in a glass and observe condensation
(C) Mix water and sand
(D) Shine light on water

3. Identify the incorrect property of gases:

(A) Gases fill the container completely
(B) Gases have no fixed volume
(C) Gases have fixed shape
(D) Gas particles are in random motion

4. During an experiment, a jar with a burning candle is inverted over water. The water level rises inside the jar. This demonstrates:

(A) Combustion produces water
(B) Air exerts pressure
(C) Volume of air increases when heated
(D) Condensation of water vapor

5. What is a hypothesis? Give an example related to plant growth.

6. State two differences between solid and gas.

7. Name two instruments used in laboratory experiments and their uses.

8. Fill in the blanks:

a) The SI unit of force is __________.
b) Milk is an example of a __________.

9. Explain the steps involved in a scientific investigation with examples.

10. Describe the difference between independent, dependent, and controlled variables in an experiment with an example.

11. Explain how science helps in understanding weather events like storms and cyclones.

12. State and explain any three differences between physical and chemical changes with examples.

13. State True or False with Reasons:

(a) Air exerts pressure.
(b) Moon produces its own light.
(c) Gases have fixed shape.
(d) Condensation is a chemical change.

14. Explain how electric current helps us in daily life and its various effects that make work easier.

15. Explain how observing the Moon’s phases and other celestial events helped humans develop the first calendars.

16. Science studies atmospheric conditions using instruments like barometers, anemometers, and hygrometers.

• These help predict storms and cyclones, track their intensity, and issue warnings.

• Knowledge of air pressure, wind speed, and humidity allows governments to evacuate people and reduce damage, showing practical application of science in daily life.

17.

• Physical change: No new substance formed (e.g., ice melting).

• Chemical change: New substance formed (e.g., burning paper).

• Other differences:

• Physical change is often reversible; chemical change is usually irreversible.

• Physical changes involve change in shape, size, or state; chemical changes involve energy release or absorption.

18. (A) Air exerts pressure. – True

Reason: Air is made up of particles that have mass and are in constant motion. These particles collide with surfaces, exerting force per unit area, which is observed as air pressure.

Example: A balloon inflates because air pressure pushes against its walls.

(B) Moon produces its own light. – False

Reason: The Moon does not generate its own light; it reflects sunlight. The Moon appears bright because sunlight bounces off its surface.

(C) Gases have fixed shape. – False

Reason: Gases do not have a fixed shape or fixed volume. Gas particles move freely and take the shape of their container.

Example: Air fills the shape of a balloon regardless of its form.

(D) Condensation is a chemical change. – False

Reason: Condensation is a physical change where water vapor turns into liquid water. No new substance is formed, and the process is reversible.

19. Electric current is essential in daily life because it helps perform many tasks efficiently. Its heating effect is used in devices like heaters, electric stoves, and irons to warm objects or cook food. The magnetic effect of current is used to operate motors, fans, and machines, enabling them to run smoothly. Electric current can also produce light, power electronic devices, and run appliances, making life more comfortable and convenient. Observing these effects of electricity helps us understand how electrical energy can be converted into useful work in different forms.

20.

1. Observation of the Moon: Ancient humans carefully watched the cyclical changes in the Moon's shape, from New Moon to Full Moon and back.

2. Linking cycles to time: They realized that lunar cycles repeat regularly, approximately every 29.5 days, which could be used to measure months.

3. Combining with the Sun: Observations of sunrises and sunsets helped track the day and year, linking lunar months to solar years.

4. Development of calendars: By recording these cycles systematically, humans created the first calendars to organize agricultural activities, festivals, and daily routines.

5. Significance: This shows that our modern schedules are influenced by motions of celestial bodies, highlighting the connection between astronomy and everyday life.

Class 8 Science Chapter 1 Important Questions PDF Download

Download the Class 8 Science Chapter 1 Important Questions PDF by PW to revise all the key concepts in one place. The PDF includes chapter-wise important questions with detailed solutions, making it an excellent resource for quick revision, regular practice, and effective exam preparation. With Physics Wallah, you can strengthen your concepts and boost your confidence before your school exams.

Benefits of Using the Important Questions PDF

The Class 8 Science Chapter 1 Important Questions PDF by PW is a handy study resource that makes exam preparation more organised and effective. It allows you to revise important topics in one place and practise questions that are commonly asked in examinations. 

Some of the key benefits include:

• Covers the most important questions from the chapter in one place.

• Helps with quick and effective revision before exams.

• Improves the understanding of key scientific concepts.

• Familiarises you with different types of exam questions.

• Enhances problem-solving and analytical thinking skills.

• Supports self-study and offline learning anytime, anywhere.

• Builds confidence through regular practice.

Practising the Class 8 Science Chapter 1 Important Questions PDF by PW is an effective way to strengthen your understanding of scientific concepts and improve exam readiness. These questions cover the key topics of the chapter, helping students revise important concepts, apply scientific thinking, and build confidence before examinations. 

Along with studying the NCERT textbook, regular practice of these important questions and their solutions will enhance problem-solving skills and improve overall performance in school exams.