What is "sweetness?" How do you define it? A fruit's sweetness varies not only with its age but also with its type, or cultivar. A cultivar is a type of plant with desired characteristics that growers have created by breeding and then maintained by cultivation. This lesson has your students create a scale that will allow them to measure and compare the sweetness of several types of apples, a non-sweet plant (potato) and a popular, sugar-sweetened soft drink.