Demand and supply elasticity

Elasticity of supply, as a response to changes in price, is related to demant. Economists define “demand” as a consumer’s desire or want, together with his willingness to pay for what he want. We can say that demand is indicated by our willingness to offer money for particular goods or services. Money has no value in itself, but serves as a means of exchange between commodities which do have a value to us.
People very seldom have everything they want. Usually we have to decide carefully how we spend our income. When we exercise our choice, we do so according to our personal scale of preferences. In this scale of preferences essential commodities come firs (food,chothing, shelter, medical expenses etc.), then the kind of luxuries which help us to be comfortable (telephone, special furniture, insurance etc.), they may all seem importent, but their true importance can be meansured by deciding which we are prepared to live without. Our decisions indicate our scale of preferences and therefore our priorities.
Elasticity of demand is a measure of the change in the quantity of a good , in response demand. The change in demand results from a change in price. Demand is inelastic when a good is regarded as a basic necessity, but particularlyelastic for non-essential commodities. Accordingly, we buy basic necessities even if the prices rise steeply, but we buy other things only when they are relatively cheap.