How do magicians make people disappear?

Answer 1

illusion, not real.

In the old days they used mirrors. Generally on a darkened stage they would have three mirrors, out of view of the audience. The magician that the audience sees is actually his reflection. There are two angled concave mirrors. When he stands in the focal point, his reflection is no longer there. Then, there is a mirror behind him and a mirror, somewhere above the audience' heads reflecting his reflected image in the background. When he gives a signal, stage hands will simultaneously cover the front and back mirror, making his reflection disappear, because the two angled mirrors are reflecting each other where there is no image of the magician present.

To know this it is a matter of physics. He has to take into account his height, the height of the mirrors and their exact angle (Snell's law: (nsinθ =nsinθ) that the mirrors have to be at. Then he can determine where their focal point is and make sure he is standing in it. Unbeknownst to the audience, they are always just seeing his reflection, and that is what he makes disappear.

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Nowadays they just use a projector (often times). The image of him/her is projected onto the stage and when he gives the signal, it is shut off.

(BORING) :]