Question

Identify the materials from the following which float in water:
(A) Wax, iron nail, sponge
(B) Plastic, wood, oil
(C) Ice, oil, sand
(D) Honey, thermocol, key

Answer 1

Hint : When the weight force on an object is compensated by the upward push of the water on the object, the object floats. The upwards push of the water is proportional to the volume of the material submerged; it is unaffected by the depth or volume of the water.

Complete Step By Step Answer:
If an object weighs more than an equivalent amount of water, it is more compact and will sink, while if it weighs less, it will float. Keep in mind that water has a density of around 1 g/cm³.
The term "density" refers to the amount of mass per unit of volume. An object's average density is proportional to its total mass divided by its total volume. An object composed of a more dense material (such as iron) would have less volume than one made of a less dense substance of comparable mass (such as water).
Wax is a buoyant substance, meaning it floats rather than sinks while submerged in water. Since wax is less solid than water, it floats. The wax molecules are able to fit together more closely as a result of this transition, increasing their density and making them heavier.
Since iron has a higher density than water, its weight is greater than the weight of water displaced by it, and the nail sinks. Water is thinner than the sponge. As a result, the sponge floats. The upthrust force exerted by the water on the empty plastic container is weaker than the gravitational pressure on it. In other words, since its density is lower than that of water, it floats.
Since wood, cork, and ice are less compact than water, they float. Since Plastic weighs less than the amount of water it will have to lift out of the bottle if it sinks, it floats. Since wood, cork, and ice are less dense than water, they float; rocks, on the other hand, are more dense and sink.
Due to the viscosity of honey, oil they are much denser than water.
Hence, option B is correct.

Note :
If the buoyancy force applied on an object by the fluid equals its weight, it will float. If the buoyant force equals one tons, it will sink no more. Any object that displaces an equivalent amount of water as its own weight floats.