Science
What this domain tests
Science covers upper-primary physics, chemistry, biology and environment: motion, force, light, sound, matter, acids and bases, cell structure, nutrition, human body systems and basic health. Questions often ask you to explain a daily-life observation.
Core rules and concepts
- Speed = distance/time; velocity includes direction; average speed depends on total distance and total time.
- Light travels in straight lines; reflection follows the law that angle of incidence equals angle of reflection.
- Sound needs a material medium; it cannot travel through vacuum.
- Photosynthesis: carbon dioxide + water + light energy → glucose + oxygen, using chlorophyll.
- Acids turn blue litmus red; bases turn red litmus blue. pH below 7 is acidic, above 7 is basic.
Worked example
A car travels 60 km at 30 km/h and returns 60 km at 60 km/h. Find its average speed. Reasoning: Total distance = 120 km. Time outward = 60/30 = 2 h; return = 60/60 = 1 h; total time = 3 h. Average speed = 120/3 = 40 km/h. The arithmetic mean 45 km/h is wrong because more time is spent at the slower speed.
Traps that cost marks
- Averaging speeds instead of dividing total distance by total time.
- Saying sound travels through vacuum.
- Confusing photosynthesis with respiration; respiration releases energy and occurs in both plants and animals.
- Mixing up litmus colour changes.
Use a simple table for distance, time and speed in motion numericals.