TOP 10 AMAZING QUESTIONS ON SCIENCE AND PHYSICS.

1. Why is it easier to lift a heavy stone underwater than in the air?

Solution: According to Archimedes' principle, when a body is immersed either wholly or partly in a fluid at rest, it experiences an upward thrust and loses weight equal to the importance of the fluid displaced by its submerged part.

Thus when the stone is put underwater, it loses weight and hence is easier to be lifted.

2. A glass tumbler is filled to the brim with water, and a piece of ice is floating on it. As the ice melts, will the water overflow or not?

Solution: The level of water in the glass tumbler will remain unchanged. According to Archimedes' principle, the weight of floating ice is equal to the importance of the water displaced by it.

Thus the volume of the water obtained by the melting of ice is precisely equal to the importance of the displaced water. That is why there is no change in the level of water in the tumbler.

3. Why does a piece of ice float on water while it sinks in alcohol?

 Solution: Ice is lighter than water, and hence it floats. It is heavier than alcohol, and so it sinks in alcohol.

4. Why does the ink from the fountain pen spill out when one carries it in the airplane?

Solution: The atmospheric air pressure at a high altitude is less than what it is at sea level.

Therefore, the air inside the fountain pen expands at high altitudes, and the ink contained inside the enclosure is pushed out. This causes spillage. 

5. Which is more elastic - a piece of glass or rubber?

Solution: Glass is more elastic than rubber. Forgiven applied stress, the strain produced in glass is much smaller than that produced in rubber.

Therefore, elasticity, defined as the ratio of stress to strain, is more significant in glass than in rubber. 

6. Why a petrol fire cannot be extinguished by pouring water over it?

Solution: Water, heavier, slips down, and petrol will rise to the surface and continue to burn, as before. Hence water cannot extinguish petrol fire.

7. Explain why passengers in a boat or a double-decker bus are not allowed to stand.

Solution: This is done so that the center of gravity of the bus is not raised, and the bus may not topple over due to unstable equilibrium. For a similar reason, passengers in a boat are not permitted to stand.

8. Why does a dead body floats in water?

Solution: Because the upthrust produced on account of displaced water by the immersed portion of the dead body is equal to the weight of the whole dead body. Hence it floats.

9. Why a small space is left at the joint between two rails?

Solution: Metals expand on heating and contract on cooling. A small space is left between each set of the two rails of the railway line to allow for their expansion in summer and contraction in winter, respectively.

10. Why does a ship rise as it enters the sea from a river?

Solution: The density of seawater is higher as compared to river water. Consequently, the upthrust produced by the seawater on the ship is more significant than the river water. This explains the reason for the rise of a boat as it enters the sea from a river.