Light. Something so simple, something we interact with everyday of our lives, has properties so complex that it’s beyond explanation. This experiment reminded me that sometimes even science can’t give us all the answers…at least not yet.
What you need: Polarizing film (An A4 sheet size on Amazon here but you could attempt this with three polarized glasses lenses), cardboard, tape, play dough, and scissors.
What you do:
- Cut the polarized sheet into three rectangles and frame with cardboard
- Use a little play dough to prop the polarizers up about 6″ apart.
- Turn the second polarizer at a 90 degree angle until the light is completely blocked out
- Place a third polarizer between the first two
- (Now this is where it gets weird…) Begin to rotate the third polarizer and you will begin to see the light shine through!
What’s the science?
Light has properties of waves and particles. Light waves are like a string travelling in different directions, up/down and left/right. Polarized film cancels out the up/down direction of the wave and by adding a second polarizer another wave direction is blocked causing the wave properties to be cancelled out.
How is it possible to add a third polarized filter that allows the light to now shine through where it was once blocked? It can only be explained that the light’s particle properties behave differently than it’s waves properties when a third polarizer is added. Quantum theory attempts to describe the probabilities of how the light particle passes through the polarizers, but in the end the properties of light are unpredictable.
I asked my 9 year old what she thought of doing science that was unexplainable and she said “those were her favorite ones.” I think that is a win in my book 😉
So light, it’s property and it’s predictability is not as simple as you think… or is it?
If you want further explanation of quantum theory visit this Popular Mechanics article here and for more experiments like this one check out the book 50 Nifty Super Science Fair Projects here.
Leave a Reply