But I don't notice a difference at all!
That's because our eyes can't really tell the difference between light that is
vertically polarized and light that is horizontally polarized. In fact, we
can't really distinguish between unpolarized and polarized light at all. Now
add the other two filters and see what happens when all three are present.
This is so cool! I can take the filter out of the middle and block the light
from the camera's view with the remaining filters. When I put the middle
filter back in, everything changes! If the middle filter is aligned with
either of the two filters, the camera still doesn't see any light. If I put
the middle filter in so that it's not aligned with either of the other lenses,
some light gets through. The most light gets through if I turn the middle lens
so that it's at a 45 degree angle to both of the other lenses.
Can you try to explain why this happens?
When the middle filter was out, I could adjust the last filter so that it
absorbed all of the light that emerged from the first filter. If I put the
middle filter in so that it was aligned with either of the other two filters,
all of the light was still absorbed. If I put the middle filter in at another
angle, it only absorbed part of the light from the first filter. This allowed
some components of the light to pass through the final filter. Adding the
middle filter caused the polarized light to no longer be completely parallel
to the strands of molecules in the final filter.
You are absolutely right! Now we can take a look at how light can be
manipulated by using many lenses.