This is one of my favorite activities! It is so exciting and has major wow factor. The activity can be done as a teacher demonstration or working in lab groups. In this K-2 version, students practice the steps of the scientific method by changing one of the variables in the experiment, making a hypothesis (prediction), observations, and conclusions. Students can follow along with the picture based procedure or text based. In this activity, a solution of yeast is mixed with a solution of hydro