Question

Give reasons for the following:
1. A sponge is a solid but can be easily compressed.
2. Clothes dry faster on windy day
3. Smell of perfume travels a few yards away

Answer 1

Solids are usually known to be packed structures which means that their atoms are arranged in fixed positions and thus have definite shape. They are known to have fixed volume and density. Liquids do not have a fixed volume and neither do gases. Liquids have fixed density but gas does not have any fixed density.

Complete step-by-step answer:
1. A sponge is a solid but can be easily compressed
Solids do not take up the shame of a container. But the sponge is solid and it can still be compressed. This is because it has air spaces which are present in the structure of the sponge. This structure is filled with air and those air spaces are the reason why the sponge is able to compress and the air is given out of these spaces when we try to compress it. When we release and relax it, the air spaces are again available for the air particles to fill them up. Thus, the sponge reverts back to its original space.
2. Clothes dry faster on windy day
As we know that evaporation is a really important process that occurs in different sectors of life, it has also different benefits which we can use it for. We know that the air around is incompressible and has indefinite volume. Thus this is the reason why evaporation can occur easily. During evaporation, the liquid state of any substance turns to the gaseous state. This occurs below the boiling point and the water turns into water vapor. In the environment, this is the reason for humidity. Thus when the wind is fast, this means that water is very rapidly evaporating into water vapors on the surface of the wet clothes. This fastens the process and thus clothes dry quickly.
3. Smell of perfume travels a few yards away
Yes, we have seen that we can smell the perfume even when it is present at a distance. We use air fresheners for unpleasant odors at different places. But why does this happen? Yes, this also has a phenomenon behind it. It is called the diffusion process. This happens with the air particles. When we spray, the air molecules of the perfume are at a higher density at one end. Diffusion is the process in which molecules move from a region of higher concentration to a region of lower concentration. This leads to the perfume particles to move faster and cover the whole yard.

Note: Diffusion can be seen to occur in roots of plants in the form of osmosis. Here there is more water concentration in soil than that in plants. This causes the movement of water molecules to occur under a concentration gradient. The water molecules move from soil to the plant root. Liquid and gases undergo diffusion as the molecules are able to move randomly.