What If?: Serious Scientific Answers to Absurd Hypothetical Questions

Question: “What would happen if a hair dryer with continuous power were turned on and put in an airtight 1x1x1-meter box?” (52).

All 1,875 watts of dryer heat will heat up the box, and the box will begin to radiate away that heat. When the box reaches 140 degrees Fahrenheit (60 degrees Celsius), it’s the same temperature as the dryer—the two are in equilibrium—and will get no hotter, while nearby objects warm up from the radiated heat.

Inside an indestructible box, an invulnerable dryer pushing 18,750 watts would heat the box to 475 degrees F, like a skillet on a low flame. A dryer and box producing a trillion watts would release the same energy as a stack of TNT the size of a house exploding every second. At 200 trillion watts, equal to all the electrical devices on Earth, the dryer box would release energy equal to three times the first atomic bomb per second; it would bounce at high speed from place to place on superheated gas, leaving a massive trail of destruction.

During Operation Plumbbob, a one-kiloton underground atom-bomb test, a manhole cover was launched upward at six times the Earth’s escape velocity, so fast that a camera caught only one frame of the cap as it rose.