a movement on the demand curve will take place when there is
Demand curve There is movement along a demand curve when a change in price causes the quantity demanded to change.[5] It is important to distinguish between movement along a demand curve, and a shift in a demand curve. Movements along a demand curve happen only when the price of the good changes.[6] When a non-price determinant of demand changes the curve shifts. These "other variables" are part of the demand function. They are "merely lumped into intercept term of a simple linear demand function." [6] Thus a change in a non-price determinant of demand is reflected in a change in the x-intercept causing the curve to shift along the x axis.[7]
Income–consumption curve The income effect in economics can be defined as the change in consumption resulting from a change in real income.[1] This income change can come from one of two sources: from external sources, or from income being freed up (or soaked up) by a decrease (or increase) in the price of a good that money is being spent on. The effect of the former type of change in available income is depicted by the income-consumption curve discussed in the remainder of this article, while the effect of the freeing-up of existing income by a price drop is discussed along with its companion effect, the substitution effect, in the article on the latter.