It is a kind of magic, isn’t it? The wind is blowing from the north, and you can sail to the northeast – almost right into the wind.
For thousands of years, it did not occur to mankind that this was even possible. We thought we had to delay our voyage until the wind was blowing the right direction. Even when the technique was finally discovered, I’ll bet nobody knew why it worked.
We now know that it relies on the same principle as another thing that was supposed to be impossible: flying a heaver-than-air craft. The principle, of course, is the airfoil, a.k.a. Bernoulli’s Principle. If you can get air to pass more quickly over one side of an object than another, then a sort of suction will pull the object toward the side that has the quicker-moving air. With a sail curved appropriately, and a keel to direct the boat, off you go into the wind!
I wonder…what other “impossible” things might we be able to do with simple but untried techniques?
How about getting to outer space by climbing a cable attached to the equator at one end and to empty space at the other? It’s simple, and will be reality once we can make a cable that is light and strong enough.
What else? Teleportation? Telepathy? Time travel? Maybe none of those, but it’s fun to wonder about.
In the meantime, here’s a fun trick you can do at home.