Discover the roles mass and volume play when determining the density of items. Start by filling the 6 plastic containers with various everyday materials such as cereal, sand, cotton balls, marshmallows, rocks, or water (not included) and give them to students. Teachers can vary the amount of materials in the jars as an added challenge. As students examine the jars, they predict the weight of the containers and place the jars from lightest to heaviest on the prediction circles on the included vinyl EvaluWeight mat. Students then work together to weigh each jar on the scale to see if their predictions were accurate. During the weighing process, they set the jars in order from lightest to heaviest along the results row on the mat and observe how weight depends on the density and volume of substances. Take lessons to the next level by having students calculate the volume of the containers and density of the materials inside. Lesson direction highlights activities that test student knowledge and is adaptable for grades K-4 and 5-8. Individual Set is ideal for a small group of up to 6 students and includes 6 plastic containers, a vinyl mat (32"L x 20"W), a digital scale, and lesson direction. Class Set includes 4 Individual Sets and accommodates an entire class. Recommended for Elementary and up.