Half Yearly Class 7 Science Set 3 | Science (Curiosity) Class 7 - New NCERT PDF Download

Time: 3 Hours
Maximum Marks: 80
General Instructions:
(i) The question paper consists of 34 questions divided into four sections: A, B, C, and D.
(ii) All questions are compulsory.
(iii) Section A: Questions 1 to 15 are multiple-choice questions, carrying 1 mark each. Select the most appropriate response.
(iv) Section B: Questions 16 to 22 are short-answer questions, carrying 2 marks each.
(v) Section C: Questions 23 to 31 are short-answer questions, carrying 4 marks each.
(vi) Section D: Questions 32 to 34 are short-answer questions, carrying 5 marks each.
(vii) Answer the questions in the space provided or on a separate answer sheet as instructed.
(viii) Use of calculators is not permitted.

Section A

Q1. The first step in understanding a natural phenomenon in science is:  (1 mark)
(a) Guessing
(b) Observing
(c) Ignoring
(d) Concluding

Q2. A substance that turns red litmus blue is:  (1 mark)
(a) Acidic
(b) Basic
(c) Neutral
(d) Salty

Q3. The component that allows or stops current flow in a circuit is:  (1 mark)
(a) Bulb
(b) Battery
(c) Switch
(d) Wire

Q4. Which of the following is a non-metal used in disinfectants?  (1 mark)
(a) Iron
(b) Chlorine
(c) Aluminium
(d) Copper

Q5. The burning of magnesium ribbon is an example of:  (1 mark)
(a) Physical change
(b) Chemical change
(c) Reversible change
(d) Temporary change

Q6. Which hormone is responsible for height increase during adolescence?  (1 mark)
(a) Estrogen
(b) Testosterone
(c) Growth hormone
(d) Adrenaline

Q7. The reaction of an acid with a base is called:  (1 mark)
(a) Evaporation
(b) Neutralization
(c) Filtration
(d) Sedimentation

Q8. Which component in a circuit produces heat when current flows?  (1 mark)
(a) Switch
(b) Fuse
(c) Heating element
(d) Battery

Q9. Which non-metal is used in making pencil leads?  (1 mark)
(a) Sulphur
(b) Carbon (graphite)
(c) Nitrogen
(d) Phosphorus

Q10. The process of obtaining pure salt from seawater is an example of:  (1 mark)
(a) Filtration
(b) Evaporation
(c) Distillation
(d) Sedimentation

Q11. Which of the following is a reversible change?  (1 mark)
(a) Burning of paper
(b) Melting of butter
(c) Cooking of rice
(d) Rusting of iron

Q12. The development of breasts in girls during adolescence is due to:  (1 mark)
(a) Testosterone
(b) Estrogen
(c) Adrenaline
(d) Growth hormone

Q13. Which material is a good conductor of heat?  (1 mark)
(a) Wood
(b) Plastic
(c) Aluminium
(d) Glass

Q14. Which indicator turns pink in a basic solution?  (1 mark)
(a) Litmus
(b) Phenolphthalein
(c) Turmeric
(d) China rose

Q15. Which of the following is a chemical change?  (1 mark)
(a) Evaporation of water
(b) Rusting of iron
(c) Cutting of vegetables
(d) Melting of wax

Section B

Q16. What role does questioning play in a scientific investigation?  (2 marks)

Q17. Name two basic substances used at home and their applications.  (2 marks)

Q18. Draw a circuit diagram with a battery, two bulbs, and a fuse in series.  (2 marks)

Q19. State one property of a metal and one property of a non-metal.  (2 marks)

Q20. Give one example each of a physical change and an irreversible change.  (2 marks)

Q21. Name two physical changes observed during adolescence in boys.  (2 marks)

Q22. Why are non-metals generally poor conductors of electricity?  (2 marks)

Section C

Q23. Describe how to test a substance using phenolphthalein as an indicator.  (4 marks)

Q24. Explain the role of a fuse and a wire in an electric circuit with a diagram.  (4 marks)

Q25. List two physical and two chemical properties of metals with examples.  (4 marks)

Q26. Explain the chemical change that occurs during the rusting of iron.  (4 marks)

Q27. Describe three physical changes and one emotional change during adolescence in boys.  (4 marks)

Q28. What is a neutralization reaction? Write the chemical equation for the reaction between hydrochloric acid and calcium hydroxide.  (4 marks)

Q29. Explain why parallel circuits are preferred in household wiring with diagrams.  (4 marks)

Q30. Why are metals used to make wires? Give two examples of metals and their uses in wiring.  (4 marks)

Q31. Describe an activity to demonstrate a chemical change by burning a piece of paper.  (4 marks)

Section D

Q32. (a) Design an activity to observe the effect of air on the burning of a candle.  (3 marks)
(b) Identify the physical and chemical changes in the activity.  (2 marks)

Q33. (a) Describe an activity to demonstrate a neutralization reaction using lemon juice and baking soda.  (3 marks)
(b) Explain how neutralization can be used to treat soil acidity.  (2 marks)

Q34. (a) Explain the importance of balanced diet and personal hygiene during adolescence.  (3 marks)
(b) Describe an activity to show the effect of a balanced diet on physical growth.  (2 marks)

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