How To: Absurd Scientific Advice for Common Real-World Problems

by Randall Munroe

Runners take advantage of aerodynamics. They wear sleek, tight-fitting outfits to cut down on air resistance, which helps them to gain greater speeds and thus soar higher.* Why not take it a step further?

People are a lot denser than air, so our terminal velocity is pretty high. A falling person’s terminal velocity is around 130 miles per hour (mph).

Unfortunately, water is heavy—ask anyone who’s ever filled a fish tank on the floor and then tried to lift it up onto a table. Gravity pulls the water downward, but the ground pushes back equally hard. The water pressure is redirected outward, toward the walls of the pool, which are stretched in all directions. This tension, called hoop stress, is strongest at the base of the wall where the water pressure is the highest. If the hoop stress exceeds the tensile strength of the wall, the wall will burst.*

Siphons are driven by atmospheric pressure, and Earth’s air pressure is only capable of pushing water up 30 feet against gravity.

High-frequency sounds are absorbed by air as they travel through it, so they fade out quickly. That’s why nearby thunder makes a higher-pitched “cracking” sound, while faraway thunder makes a low rumble. They both sound the same at the source, but over a long distance, the high-frequency components of the thunder are muffled and only the low-frequency ones reach your ear.