vitÂ·riÂ·fy (vÄ­tâ²rÉ-fÄ«â²) v. vitÂ·riÂ·fied, vitÂ·riÂ·fyÂ·ing, vitÂ·riÂ·fies v.tr. To change or make into glass or a glassy substance, especially through heat fusion. v.intr. To become vitreous.
We draw a demand curve to show the relationship between the price of the good and the quantity that consumers are willing to buy. For example, suppose people are willing to buy 20 pounds of strawberries at a price of $2, but are willing to buy 30 pounds if the price falls to $1.
* As a final exercise in using graphs, suppose that some determinant of quantity demanded other than price changes; then the demand curve shifts. If the change increases quantity demanded at any given price (e.g., consumer incomes rise), then the demand curve shifts to the right.