In the video, the magician claims that this is the best coin trick in the world. It is indeed a good trick and anyone could learn to do it. He demonstrates the trick, and then reveals how a magician pulls it off:

If you are so inclined, you can fast forward to the 4 minute point and skip the introduction.

How does this trick work? What principles are being used here? There is a minor amount of slight-of-hand, but that really isn’t important. The important technique is using assumptions that human beings make about the world. We assume that the American coin and the Mexican coin are real and whole. It does not really occur to the “average viewer” that a hollowed-out 50-cent piece exists, or that there is a coin that looks like a Mexican copper coin on one side and an American silver coin on the other. That assumption is so strong that, when watching the trick, we never consider the possibility. It is only when the trick is revealed that the “I get it” moment occurs.

The way to avoid getting tricked would be to ask to see the coins as soon as they are presented to guarantee that they really are real. You would make no assumption about the reality of the coins until their reality is demonstrated.

On the other hand, if you are a magician and you want to create a new trick, or if you are a budding magician trying to learn the craft, you would understand that human beings do typically make assumptions like this. You can use the assumption to your advantage. You can also see that there are ways to help the assumption along. For example, in the video the magician adds a little description of the Mexican copper coin to subtly reinforce the idea in your mind that the coin he holds is real. It is a form of distraction as well – it distracts the viewer’s mind from asking the “is it real” question.