YOUR TAX-DEDUCTIBLE CONTRIBUTION PURCHASES THIS ITEM FOR OCS - THANK YOU! In this demonstration, students are asked to form a mental picture of an object hidden beneath a cardboard blind. Students must formulate hypotheses about the size, shape, and composition of the object while watching you probe the object with a laser beam. Students are actively engaged throughout this demonstration exercise about indirect observation as they develop a deeper understanding of how scientists such as Rutherford knew without seeing.