Question

Name three things that are lighter than water
A.Oil, wood , fax
B.Iron, silver and gold
C.Sodium, potassium and aluminum
D.Plastic, glass and wool

Answer 1

Hint: The density of an object determines whether it will float or sink in another substance. An object will float if it is less dense than the liquid it is placed in. An object will sink if it is denser than the liquid it is placed in.

Complete answer:
Whether an object floats or sinks in water depends on how dense, or compact, its particles are. An object will sink in water if it is made up of particles that are more tightly packed together than the particles in water. An object that is less dense than water will float.
Water is heavier than oil for the same unit volume due to its higher density. Due to its larger mass, it settles at the lowest level to have the smallest potential energy and is able to do so as water is fluid. So the water body is positioned below the oil body.
If you compared the weight of wood and an equal amount, or volume, of water the sample of wood would weigh less than the sample of water. This means that wood is less dense than water. Since wood is less dense than water, wood floats in water, no matter how big or small the piece of wood is.
So, the correct answer is A) oil, wood and fax.

Note:
Objects are made up of very tiny molecules. Molecules can be packed in close together like in a rock or more spread out like in bubble wrap. The positioning of molecules affects the density of an object. Objects with tightly packed molecules are denser than those where the molecules are spread out. Hollow things often float too as air is less dense than water.