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.
If you are still confused as to why the demand curve slopes downwards, plotting the points of demand curve may make things more clear. In this example, start by plotting the points in the demand schedule on the left. With price on the y-axis and quantity on the x-axis, plot out the points given the price and quantity. Then, connect the dots.