At first, making the distinction between demand and quantity demand was a little hard for me. I kept confusing the two terms and described them as if they were the same things in an economic analysis. However, after some careful reading and practice problems, I am finally able to identify one from the other, very clearly. In any market, demand refers to how much of a product or service is desired by consumers at several different prices. This is graphically illustrated by what is called the demand curve. Demand can either shift to the right if it increase or to the left when it decreases. There are several factors that contribute to the shift of demand. These factors are, population changes, popularity, prices of related goods or services (substitutes and complements), income, tastes, expectations and the number of consumers. Now, these are not set in stone as the only factors effecting demand. There are probably many other reasons, but these are the most likely reasons for a shift. In terms of quantity demanded, this refers to the desired amount of a product or service at a specific price. This is graphically illustrated by a dot on the demand curve. Unlike a change in demand, a change in quantity demanded is reflected by a movement along the curve. A change in quantity demanded corresponds with the law of demand, which states that if the price of a good increases, consumers will desire less of it and vice versa. When the price of a good or service increases, the quantity demanded decreases, causing a downward movement along the curve. If the price decreases, there will be an upward movement along the curve. Unlike the many factors that can shift the demand, price is the only factor that can affect the quantity demand. .
As a college student living on my own, I am very familiar with the concept of "substitute " goods. When the price of one good rises, the consumer will most likely lean towards purchasing the alternative good, which is almost the same amount of satisfaction, but for a cheaper price.
