Kerala PSC Everyday Science Questions & Answers 2026 – Download 50 MCQs PDF

Kerala PSC Everyday Science Model Questions & Answers 2026

Section 1: Kitchen and Food Science

1. Why does adding salt to water increase its boiling point?
Salt raises the boiling point through a phenomenon called boiling point elevation — dissolved particles disrupt the water’s ability to form vapor bubbles easily, requiring more heat energy.

2. Why do onions cause tears when cut?
Cutting onions releases a volatile compound (syn-propanethial-S-oxide) that irritates the eyes, triggering tear glands to flush it out.

3. Why does milk curdle when lemon juice is added?
The acid in lemon juice lowers the pH of milk, causing milk proteins (casein) to denature and clump together.

4. Why is a pressure cooker able to cook food faster than an open pan?
Sealed steam increases internal pressure, which raises the boiling point of water above 100°C, cooking food faster at higher temperatures.

5. Why does ice float on water instead of sinking?
Ice is less dense than liquid water because its molecules form an open hexagonal crystal structure when frozen, occupying more space than in liquid form.

Section 2: Health and Human Body Observations

6. Why do we feel thirsty after eating salty food?
Excess sodium increases blood osmotic pressure, prompting the brain’s hypothalamus to trigger thirst so the body can restore fluid balance.

7. Why does skin wrinkle after staying in water for a long time?
Prolonged water exposure causes the outer skin layer to absorb water and swell, and the body’s nervous system also actively wrinkles skin on fingers/toes to improve grip in wet conditions.

8. Why do we see stars even after closing our eyes in a dark room?
This is due to spontaneous activity in the retina’s photoreceptor cells, which can fire signals even without external light, a phenomenon called phosphenes.

9. Why does the body shiver in cold weather?
Shivering is an involuntary muscle contraction that generates heat to help maintain core body temperature.

10. Why do fingers appear wrinkled but the rest of the body doesn’t after a bath?
Fingers and toes have a unique nerve response that triggers blood vessel constriction under the skin specifically in these areas when wet, unlike the rest of the body.

Section 3: Weather, Light, and Natural Phenomena

11. Why does the sky appear red during sunrise and sunset?
At low sun angles, sunlight passes through more atmosphere, scattering shorter blue wavelengths away and leaving longer red and orange wavelengths visible.

12. Why do we hear thunder after seeing lightning?
Light travels much faster than sound, so the flash of lightning reaches our eyes almost instantly while the sound takes longer to arrive.

13. Why does a mirage appear on hot roads?
Hot air near the ground has a lower refractive index than cooler air above, bending light rays and creating an illusion of water on the road surface.

14. Why does dew form on grass during early mornings?
Warm, moisture-laden air cools overnight and reaches its dew point, causing water vapor to condense on cooler surfaces like grass.

15. Why do clothes dry faster on a windy day than a calm day?
Wind continuously removes the layer of moist air near the fabric surface, speeding up the rate of evaporation.

Section 4: Household Technology and Practical Physics

16. Why does a metal spoon feel colder than a wooden spoon at the same room temperature?
Metal is a better conductor of heat and draws heat away from the hand faster than wood, creating the sensation of being colder even though both are at the same temperature.

17. Why does a fan feel cooling even though it doesn’t lower room temperature?
Moving air increases the rate of sweat evaporation from the skin, which has a cooling effect on the body even though the air temperature itself remains unchanged.

18. Why do we use silica gel packets in food and medicine packaging?
Silica gel is a desiccant that absorbs moisture from the surrounding air, preventing dampness and spoilage inside sealed packaging.

19. Why does a soda bottle fizz more when opened after shaking?
Shaking releases dissolved carbon dioxide from the liquid into small bubbles that cling to the container walls; opening the bottle causes rapid pressure release, forcing these bubbles out suddenly.

20. Why does glass appear transparent while wood does not?
Glass has a uniform, non-crystalline molecular structure that allows light to pass through with minimal scattering, while wood’s fibrous, irregular structure scatters and absorbs light.

Section 5: Common Misconceptions and Practical Reasoning

21. Does a heavier object always fall faster than a lighter one in a vacuum?
No — in the absence of air resistance, all objects fall at the same rate regardless of mass, as demonstrated by Galileo’s famous (disputed) Leaning Tower of Pisa experiment and later confirmed in vacuum chamber tests.

22. Why does hot water sometimes freeze faster than cold water?
This counterintuitive observation, known as the Mpemba effect, is linked to factors like evaporation, convection currents, and dissolved gas content, though scientists still debate the exact mechanism.

23. Why does touching a 9-volt battery to the tongue produce a tingling sensation but not with the hand?
The tongue’s moist surface and thinner skin allow a small current to complete a circuit and stimulate nerve endings, producing a mild tingling sensation not felt on drier, thicker skin.