As a culminating activity to our unit on matter, fourth graders rotated through stations each investigating a different concept of matter. At the buoyancy station, students tried to change the shapes of clay and foil to make them float. Students also observed two cans of soda; one regular and one sugar free to discover that one of them floats while one sinks. Why? The sugar in the regular soda makes it more dense and therefore sink. The density station allowed students to mix various liquids and watch them separate according to their densities. While participating at the volume station, students measured volume using graduated cylinders and (colored) water. Finally at the mass station students used a balance scale and weights to determine the mass of a determined number of cotton balls. During these station activities, fourth graders were able to apply the concepts they learned in previous classes in order to measure and observe matter in multiple ways. Upon the completion of each station, students easily illustrated and wrote about each concept.