UPSC Interview Prep: 7 Tricky Science Questions Every IAS Aspirant Must Know

Published : Dec 12, 2025, 10:53 AM IST

Prepare for the UPSC interview with 7 tricky science questions that look simple but require strong logic and understanding. Learn real-life scientific questions asked in IAS interviews with accurate answers.

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Tricky science questions asked in the UPSC interview

The UPSC interview tests more than facts. The panel assesses how you analyze and explain everyday phenomena. Science questions may seem simple but require logical, scientific answers.

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Why do chameleons change colour?

Answer: For communication, camouflage, and managing body temperature. Chameleons have special cells that change colour based on light and signals to communicate or blend in.

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Why does a drop of oil spread on water?

Answer: Because water's surface tension is higher than oil's. Water has strong surface tension. When oil hits water, it spreads out as it's energetically easier.

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Why are human eyes blue?

Answer: Low melanin in the iris or structural scattering makes them look blue. Eye colour depends on melanin. With less melanin, the iris scatters light, making it appear blue.

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Why are liquid drops spherical?

Answer: Due to surface tension, a spherical shape minimizes surface area. A liquid's surface tries to be as small as possible, so particles form a sphere, the most compact shape.

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Why does a cyclist lean on a turn?

Answer: To maintain balance and avoid falling. When turning, a cyclist needs centripetal force. Leaning adjusts the centre of gravity to balance this force and gravity.

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Why does the sky appear blue?

Answer: Small air particles in the atmosphere scatter blue light more, a process called Rayleigh scattering. Sunlight has all colours, but blue light scatters most in the air.

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Why do bubbles form when water boils?

Answer: When water heats up, it turns into steam, which rises as gas bubbles. A liquid boils when its internal vapour pressure equals the external air pressure, forming bubbles.

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