Discovering the Charge of an Electron - Analogy of Millikan's Oil-Drop Experiment - Laboratory Kit
By: Earl Pearson, Middle Tennessee State University, Murfreesboro, TN
Item #: AP7350
The Discovering the Charge of an Electron Chemistry Laboratory Kit helps students comprehend the atomic theory of matter. BBs attracted to magnets represent electrons. Students measure and analyze data to find the mass of one BB.
The electron, an elementary particle of matter, has a negative charge. Exactly how much electrical charge does one electron have? In the early twentieth century, Robert Millikan quantified the charge of a single electron through a series of carefully designed experiments using electrically-charged oil drops. In this analogous activity, BBs attracted to magnets of various sizes represent electrons on the oil drops. After making careful measurements, students analyze the data to determine the mass of one BB—using the same reasoning employed by Millikan in his oil-drop experiments—without weighing any known quantity of BBs! A great activity to help students understand the development of the atomic theory of matter from a historical perspective. Complete for 30 students working in pairs. Balances with 0.01-g precision are recommended.