Black body radiation

A blackbody radiation demonstration suitable for showing students that objects that absorb radiation effectively also emit thermal radiation effectively. All matter emits electromagnetic radiation due to the vibrations of the charged particles of which it is composed. How¬†much¬†electromagnetic radiation (EMR) an object emits at a certain frequency depends upon its temperature (hotter charges oscillate more … Read more…

The Paddle-wheel cathode ray tube does not prove that electrons have momentum

The Australian NSW HSC physics syllabus asks students to analyse the operation of a number of cathode ray tubes, including a tube with a paddlewheel which appears to be ‘pushed along’ by the cathode rays. Students are often expected to say that this experiment provides proof that cathode rays consist of particles (electrons) which carry … Read more…