The video by Richard Hartel, professor of food engineering at the University of Wisconsin-Madison, demonstrates how the molten liquid candy cools to form what from a technical standpoint actually is a glass. Unlike window glass made of silica, this tasty glass is made of sugar.
Viscosity describes a fluid’s internal resistance to flow and may be thought of as a measure of fluid friction. Water has very little viscosity (unless it is frozen). Thick honey has higher viscosity (especially if it is cooler – I keep my honey in the fridge and it does not flow very quickly).
As I have said before if I had understood the chemistry behind cooking as a kid I think I would have been much more interested in cooking.