|A projector for us to see the demonstration of light acting like a particle|
An expansion on the theory was that anything could have a wave form. They tested this with electrons, since electrons are quite tiny. If electrons can act as waves, then they should be able to diffract. Penn has a lot of cool devices. We used a cathode ray tube to shine a beam of electrons through a crystal lattice. Sure enough, it diffracted. We then moved on to talking about Planck's constant. This number explains the relationship between energy and frequency. It is incredibly interesting. The lecture continued to talk about all kinds of aspects of the theory.
|The screen of the electron beam device|
After the guest speaker, I had lunch. After that, we did a lab to see if Planck's constant actually worked. The number is a ratio of energy over frequency, so we measured both variables for a variety of colored LEDs. We had amazingly close data, 7x10-34, while the accepted value is about 6.6x10-34. Today has been one of my favorite days, topic-wise, in class so far. I felt like I learned a huge amount that wasn't taught in my physics class.