Class: 9 Subject: Science
Chapter: Exploration: Entering the World of Secondary Science
Maximum Marks: 50
Suggested Time: 1 Hour 30 Minutes
General Instructions
- All questions are compulsory.
- Write answers clearly and use scientific terms wherever appropriate.
- Show reasoning for questions involving estimation or application.
- The paper contains questions of different types and difficulty levels.
Section A — Objective Questions
10 × 1 = 10 marks
Q1. Science uses models mainly because:
a) models are always exact copies of reality
b) natural systems can be complex and models help simplify them
c) models eliminate the need for observations
d) models are used only in physics
Q2. Which of the following is a standard SI unit?
a) kilogram
b) foot
c) pound
d) gallon
Q3. In a scientific model, deliberately ignoring some details is:
a) always a mistake
b) useful when those details are not important for the question
c) evidence that the model is false
d) prohibited
Q4. A scientific theory is best described as:
a) an untested guess
b) an explanation supported by evidence and testing
c) an opinion held by a scientist
d) a mathematical calculation only
Q5. Which quantity is represented by the symbol m in many scientific contexts?
a) mass
b) metre only
c) momentum only
d) motion
Q6. A prediction becomes scientifically useful when it is:
a) based only on personal belief
b) impossible to test
c) based on evidence and can be compared with observations
d) always correct
Q7. An approximate answer is particularly useful when:
a) an exact laboratory measurement is required
b) a quick check of whether a result is reasonable is needed
c) medicine dosage is being calculated
d) a precise engineering measurement is required
Q8. Which example best shows interdisciplinary science?
a) memorising a definition
b) studying a mobile phone using ideas from physics, chemistry and mathematics
c) learning one scientific symbol
d) reading a single numerical value
Q9. A law generally describes:
a) a regular pattern observed in nature
b) a personal opinion
c) a random guess
d) an untested explanation
Q10. If a prediction disagrees with observations, scientists should first:
a) ignore the observations
b) change the observations
c) re-examine the assumptions, model or measurements
d) declare science useless
Section B — Very Short Answer
5 × 2 = 10 marks
Q11. What is a scientific model? Give one example.
Q12. Why are standard units important in science?
Q13. Distinguish between an approximate value and an exact value.
Q14. What is meant by a scientific prediction?
Q15. Why can mathematics be called a language of science?
Section C — Short Answer Questions
4 × 3 = 12 marks
Q16. A student wants to model the time taken to cycle from school to home. State three important details that should be considered and two details that could reasonably be ignored.
Q17. Explain why a scientific model may be changed or improved later.
Q18. Differentiate between a scientific law and a scientific theory.
Q19. A student says, “The sky is dark, so it will definitely rain.” Explain how this statement could be converted into a more scientific prediction.
Section D — Application-Based Questions
2 × 4 = 8 marks
Q20. A student estimates that one breath contains about 0.5 L of air and that a person takes about 20,000 breaths per day.
a) Estimate the total volume of air breathed in one day.
b) Why is this called an estimate rather than an exact measurement?
c) Give one reason why estimation is useful in science.
Q21. A family is planning a one-day journey by car. They want to estimate the travel time.
a) Name two quantities they should consider.
b) Why might the actual travel time differ from the estimate?
c) State one detail that could be ignored in a simple model.
Section E — Long Answer Questions
2 × 5 = 10 marks
Q22. Explain why scientists deliberately simplify complex systems while building models. Use two examples from different branches of science.
Q23. Explain the role of observation, evidence, testing and revision in scientific thinking. Why is being open to correction an important strength of science?