Question
Question: A sponge can be pressed easily; still it is called a solid, why?...
A sponge can be pressed easily; still it is called a solid, why?
Solution
Hint- In order to deal with this question first we will define the solid state, then we will proceed further by knowing the properties required by a substance to be called a solid and further we will see if sponge fulfills the criterion for being a solid or not.
Complete answer:
Solid is a property of an object that shows its shape, size, volume, density and has closely bonded molecules that show elasticity.
A sponge is a flexible solid with many minute pores which are usually filled with air. It is flexible as the sponge can be pressed into the air holes and when the pressure is released the sponge returns it to its former shape. As the sponge does not change its shape by its own if kept in another vessel and also it does not flow on its own so it satisfies the basic criterion for being a solid.
Hence, sponge is called solid.
Additional information-
Solid is one of the four main states of matter (the others are air, gas and plasma). In a solid the molecules are bundled tightly together and contain the least amount of kinetic energy. Structural rigidity and resistance to a force applied to the surface are characteristic of a solid. Unlike a liquid, a solid substance does not float to take on its container form nor does it extend to fill the full volume available as a gas. The atoms in a solid are bound together, either in a normal geometric lattice (crystalline solids like metals and ordinary ice), or irregularly (an amorphous solid like common window glass). Unable to compact the solids.
Note- Synthetic sponges may be made of polyester, polyurethane or cellulose of a vegetable type. Polyurethane is added to their abrasive surface in polyester sponges. Polyester sponges are more used in dish washing and are typically yellow and fluffy. A sponge is an instrument or a cleaning aid made from soft, porous material. Typically used to clean impervious surfaces, the sponges are particularly good for water absorption and water-based solutions.