Young’s Double Slit Experiment

Updated: Feb 25, 2018

OnThursday, B. came into the Dragon Coding Club, but indicated he wasn’t going to be able to stay–he was doing a physics experiment. The Dragon Coders were still settling in, chatting and snacking, when a voice down the hall called out something about “experiencing a universe beyond the laws of classical physics”. Of course, at The Dragon it is framed like a quest. So the rest of us came along with B. to the darkened room see the experiment in action. 

Physics teacher Ting Wang and his students had set up an after-school extension to the physics class to show a variant of the (amazing) wave-partial duality experiment called “Young’s Double Slit Experiment”. It also happens to have been one of the experiments that essentially overturned human understanding of the nature of light and later of matter; or as a student pointed out, [WAS this a student or a member of the scientific community?] “in classical physics it just shouldn’t do this”.  Dragon’s replication was MacGyver’d together with a hair, Scotch tape and a laser pointer aimed at a whiteboard on the far side of the room. A student traced the interference pattern on the whiteboard. (With a bit of trigonometry, this pattern  can ultimately be used to measure either the diameter of the hair or the wavelength of the light ).  The students, always curious, moved on to discussing some unexpected vertical effects on the beam of light, and to exploring whether there could be marks on the lens or diffraction from a small opening.  Everyone was pretty excited and busy speculating about further interesting and sometimes tangential extensions to this experiment (from the strange effects of measurement on light, to philosophical implications of entanglement, etc.)

It struck me that it was an amazing science experience that almost off-handedly touched on the ideas of curiosity, hypothesis and experimentation., seriously engaging with each other about big ideas while bringing experiments down to earth.  I was initially going to describe it as “accessible” to the Dragon scholars, but, that is very much the wrong word because “accessible” and “down to earth” still sound too passive.  It was really much more about “nurturing the seed” or “lighting the fire” than it was about “filling the vessel”.

I shared the story with my older son, who has done this experiment in grade 12 physics at another great school.  In his case it was done in class with some fancy looking lasers and a diffraction grating presumably ordered from some science education store.  I understand the experiment was presented as a “sage on stage” and produced no interesting anomaly or exploration. He honestly loved the idea of how much better it would have been to have experienced the $5 dollar laser pointer + hair+ whiteboard version, especially when followed up with the “real” experimental dialog. 

As he was facilitating and encouraging the group, I am not sure whether Mr. Wang even noticed the experience as being particularly unique per se; perhaps it’s routine for that class. But I wanted to pass along that it was awesome and highlight it was special in a couple of ways that those of us who have studied and love science really appreciate.  In my opinion it was a great example of what, at its best, the Dragon Academy can be.

–A Dragon Father

35 Prince Arthur Avenue

M5R 1B2

Toronto, On.

Tel: (416) 323-3243

Fax: (416) 323-7780

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