Class 5 EVS

# Experiments With Water

## Floats or Sinks

Question 1: What will happen when you put a puffed puri in a bowl of water? Would it sink or float?

Question 2: What will happen when you put a steel plate on water? Would it sink or float? What would happen to a spoon?

Answer: The steel plate will float on water. The spoon will sink in water.

Question 3: Would the cap of a plastic bottle sink or float on water?

Answer: The cap of plastic bottle will sink in water.

## Experiment

Take a big pot filled with water. Take things given in the table. Put each item one-by-one in water. Write your observations.

Things You Put in WaterFloats
Empty bowlYes
Bowl with 6-7 small pebbles in itNo
Iron nailNo
MatchstickYes
Empty plastic bottle with lid closedYes
Bottle half filled with waterYes
Fully filled bottleNo
Aluminium foil open and spread outYes
Aluminium foil rolled into a ballNo
Aluminium foil shaped like a bowlYes
Soap cakeNo
Soap cake in soap caseYes
Ice cubeYes

Some objects float on water, while some others sink in water. Some objects are lighter than water. Such objects float on water. Some objects are heavier than water. Such objects sink in water.

But a ship is heavier than a nail. Yet the nail sinks in water, while the ship floats on water. Why does this happen?

Whenever an object is immersed in water, the object displaces some water. There are two possibilities.

• If the weight of the displaced water is more than the weight of the object, the object floats on water.
• If the weight of the displaced water is less than the weight of the object, the object sinks in water.

A ship displaces is huge amount of water. The ship is lighter than the water displaced by it. That is why, the ship floats on water.

A needle also displaces water. But nail is heavier than the water displaced by it. That is why, a nail sinks in water.

A steel bowl displaces water. The steel bowl is lighter than water displaced by it. That is why, a steel bowl floats on water.

A steel spoon also displaces water. The spoon is heavier than water displaced by it. That is why, a spoon sinks in water.