Let’s look at one example session of the “Mystery of Light” class (Y7-10).
This session is halfway through the curriculum, and we have already experimented with laser pointers and have learned that light actually behaves like a wave when it hits an opening (slit).
Light is a wave
This is a very cool thing in itself as it is very counter-intuitive for the kids. How can one laser light produce multiple dots on a screen behind a slit??? To see the reaction of the kids is in itself one of the highlights of this class.
Use Light to measure the thickness of human hair
Now we are learning that the same phenomenon happens if light hits an object (notice the multiple dots on the back screen).
Only one simple equation allows us to tie together the wavelength of the laser (we know that by looking at the specification), the distance between the dots on the screen (we will measure that) and the width of the slit or object.
Now its time to put this into practice and we’ll have a competition whose hair is the thickest. So we simply pick one hair.
Point the laser at it and measure the distance between the dots and… we have the thickness of the hair
Results
We will learn that that hair has a thickness of 0.07 to 0.12 millimeters. Blonde hair has a lesser thickness due to a weaker middle layer. The process of aging and genetic disorders can lead to a significant reduction in the diameter.
And all that just with the power of light… Wow 🙂