Cathode Ray Tube Classroom Activity

A class activity sheet accompanies the cathode ray tube demonstrations and experiments.  The activity sheet has diagrams of each of the cathode ray tubes used in the demonstration.  The diagrams help students understand the significance of each experiment.  The activity sheet has embedded questions designed to promote small group discussions. A series of cathode ray tubes graphically demonstrate various properties of the electron. Cathode Ray Tube #12 provides evidence that cathode rays are not visible to human eyes. Cathode Ray Tube #14 - cathode rays cast a shadow behind a Maltese Cross. Cathode Ray Tube #16 - light shined on a pinwheel inside a CRT does not cause the pinwheel to move.  However, when cathode rays strike the pinwheel inside the CRT, the pinwheel begins to spin and move.  Cathode Ray Tube # 18 - in a darkened room, the electron beam (cathode rays) shows up on a phosphor screen as a bright blue line.  The electron beam is deflected by an electric field and a magnetic field.  A block Power Point presentation used to facilitate the demonstrations and the class activity is available. Clicker questions assess student understanding of how the cathode ray tubes led to scientists understanding of the properties of electrons.

© Copyright 2012 Email: Randy Sullivan, University of Oregon Chemistry Department and UO Libraries Interactive Media Group