At some point in your life, you've probably played this game of logic known as the missing square puzzle, or Curry's paradox - named after its inventor Paul Curry. This optical illusion is commonly used in mathematics classes to help students reason about geometrical figures, or rather to teach them to not reason using figures, but only using the textual description thereof and the axioms of geometry. It depicts two arrangements made of similar shapes in slightly different configurations. Each apparently forms a 13×5 right-angled triangle, but one has a 1×1 hole in it.

As depicted in the animation, the illusion works because the diagonal of the two internal triangles is not a continuous slope from corner to corner. The overall connected shap ...

Here's what happens when you pour 1 984°F/1 085°C molten copper on a Big Mac. This demonstration has nothing to do with the fact that McDonald's uses preservatives in its ingredients. This is simply a demonstration of the Leidenfrost effect - a scientific principle explaining the phenomena that occurs when a liquid comes in near contact with a solid that is significantly hotter than its boiling point; the surface of the liquid comes to a nearly immediate boil, and creates a thin layer of protective steam. It's much the same effect as when one drops water onto a hot pan and the droplet is seen to dance across the surface. In this instance, the inherent moisture in the burger protects it for a few moments before the copper (at nearly 2 000 d ...