Environment and Solar System (Class 3)

What this worksheet covers

This is a fifteen-question practice worksheet on our environment and the solar system for Class 3, written to the pattern of the SOF National Science Olympiad (NSO). It carries 21 marks and is designed to be attempted in 40 minutes, split across three sections — Scientific Reasoning, Applying What You Know and Achievers Section. Every question is multiple choice with exactly one correct option, and every one comes with a fully worked solution rather than just an answer key — so a child who gets one wrong can see where the reasoning went astray instead of only learning that it did.

Skills your child practises

• Applied problem-solving on our environment and the solar system at Class 3 level
• Working accurately against a time limit, as the real paper demands
• Scientific Reasoning questions in the olympiad format
• Applying What You Know questions in the olympiad format
• Achievers Section questions in the olympiad format
• Reading worked solutions to find the step that went wrong

How to use it

1. 1There are 15 questions in this worksheet. All questions are compulsory.
2. 2Each question has four options (A), (B), (C) and (D). Exactly one option is correct.
3. 3Questions 1–12 carry 1 mark each. Questions 13–15 (Achievers Section) carry 3 marks each.
4. 4There is no negative marking. Study every diagram and table carefully.

Sample questions from this worksheet

A preview of what's inside Environment and Solar System (Class 3) — the PDF has the full set, and every question comes with a worked solution like these.

1. 1. How many planets are there in our solar system?

   • AEightcorrect
   • BSeven
   • CNine
   • DTen
   Solution: There are eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Pluto was counted as a planet until 2006, when it was reclassified as a dwarf planet.

2. 2. Why are the stars not seen during the day?

   • AThey stop shining in the day
   • BClouds always cover them
   • CThey move to the other side of the earth
   • DThe bright sunlight in the sky hides their faint lightcorrect
   Solution: The stars shine all the time. During the day, sunlight scattered by the atmosphere makes the whole sky so bright that their far fainter light cannot be picked out — much as a candle is invisible beside a floodlight.

3. 3. Consider the following statements.(i) The moon produces its own light.(ii) Planting trees helps reduce the amount of carbon dioxide in the air.(iii) The earth takes about 365 days to go once round the sun.Which of the statements is/are correct?

   • A(i) and (ii) only
   • B(ii) and (iii) onlycorrect
   • C(i) and (iii) only
   • DAll three
   Solution: Statement (i) is false — the moon has no light of its own and merely reflects sunlight. Statement (ii) is true; trees absorb carbon dioxide during photosynthesis. Statement (iii) is true; that is why our calendar year is 365 days, with an extra day every fourth year. Hence (ii) and (iii).