Science Olympiad Practice Test for Classes 3 to 5

Answers and explanations

1. 1BSkip one letter each time: A (b) C (d) E (f) G (h) I.
2. 2DA bat is a mammal. The eagle, sparrow and parrot are birds.
3. 3AFrom the two words: S = 2, E = 1, A = 4, R = 6, C = 7 and H = 3.
4. 4CA left turn from north faces west.
5. 5BPlace from the right = 6 − 3 + 1 = 4th.
6. 6BLeaves make food by photosynthesis, using sunlight, water and carbon dioxide.
7. 7CPlants take in carbon dioxide from the air and give out oxygen.
8. 8AWhales breathe air and feed their young on milk. A shark is a fish, a crocodile a reptile and a penguin a bird.
9. 9DA liquid turning into a solid is freezing.
10. 10CThe Sun makes its own light. The Moon, mirrors and diamonds only reflect light.
11. 11DThe heart is a muscle that pumps blood all around the body.
12. 12AMagnets attract iron and steel, not plastic, wood or rubber.
13. 13BThe order from the Sun is Mercury, Venus, Earth, Mars.
14. 14CA stone does not grow, eat or reproduce. A seed is alive, waiting to grow.
15. 15DIncisors, at the front, cut. Canines tear, and premolars and molars grind.
16. 16AMetals such as copper are good conductors. Glass, rubber and dry wood are insulators.
17. 17BFrogs lay their eggs in water, where the tadpoles hatch and grow.
18. 18CSunlight on the skin helps the body make vitamin D, which keeps bones strong.
19. 19DGravity pulls everything towards the Earth; that is why things fall.
20. 20AA cow is a herbivore. Lions and eagles eat meat, and frogs eat insects.
21. 21BA thermometer measures how hot or cold something is.
22. 22CWater expands when it freezes, so ice is less dense than water and floats.
23. 23DBoth happen together, but light reaches us almost at once while sound takes about 3 seconds to travel 1 km.
24. 24APlants need sunlight to make food and to stay green.
25. 25BThe Earth goes round the Sun once a year and spins once a day; the Moon only reflects sunlight.