  While Bernoulli's equation is one of the most frequently mentioned topics in
Physics literature and other means of dissemination, it is also one of the
least understood. Oddly enough, in the wonderful book "Turning the world inside
out" [1], Robert Ehrlich proposes a demonstration that consists of blowing a
quarter dollar coin into a cup, incorrectly explained using Bernoulli's
equation. In the present work, we have adapted the demonstration to show
situations in which the coin jumps into the cup and others in which it does
not, proving that the explanation based on Bernoulli's is flawed. Our
demonstration is useful to tackle the common misconception, stemming from the
incorrect use of Bernoulli's equation, that higher velocity invariably means
lower pressure.
