Controlling the speed of Light…It can be done

Here’s one of my favorite demonstrations that is fun for kids…and good
for gemologists and jewelers. Its a rather simple but graphic
demonstration of the refraction or bending of light by controlling
the speed at which it travels. “Can we control the speed
of light?” you may ask? Well, look below and decide for yourself.

To understand this demonstration we need
to first see what it happening. What we are doing is observing
light as it travels through various mediums. The denser the medium,
the slower light has to travel. And the more its speed is slowed
up, the more it bends the direction of travel. This is called
the refraction of light, and is how a refractometer works, by
measuring how much bending a beam of light will do in a gemstone.
For our purposes we are going to use air, water and heavy water
to demonstrate this refractive index. Here’s how it works:

Well we did it. We controlled the speed
of light. Buzz Lightyear couldn’t even do that. This is just a
simple demonstration of a rather complicated lesson in physics…but
sometimes the simple explanations are better and more fun. You
can do this demonstration at home but just make sure you have
permission to use the sugar. Never know when you might need to
sweeten someone up in your house. You can learn much more about the behavior of light and how we can measure its path and speed for the use in gem identification by joining us in the International School of Gemology.