Mental Muscles of Steel

STEP 4: BEEF UP ON THE FUNDAMENTALS

You've shed counterproductive and backward notions. Now it's time to absorb some of the basic knowledge that distinguishes the
science literati from the ignorati.


Know the Major Milestones: The worldview-shaping experiments everyone should understand.

Flying clocks

The most celebrated experimental backing for special relativity came in 1971, when four cesium atomic beam clocks were flown around the world. Einstein's
theory predicted the clocks would lose 40 23 nanoseconds compared with reference clocks on the ground when circling the globe eastward, and gain 275 21 nanoseconds when traveling west. The results: a loss of
59 10 nanoseconds eastbound and a westbound gain of 273 7 nanoseconds—evidence that time is not absolute but dependent on frame of reference.


Primordial Soup

Could life have emerged from the conditions on early Earth without divine intervention? In 1953 chemists Stanley Miller and Harold Urey of the University of Chicago filled a glass bulb with hydrogen, methane, ammonia and water to simulate the early atmosphere, then heated it with a Bunsen burner "sun" and battered it with electric "lightning bolts." After a few weeks, the bulb held a reddish-brown soup containing amino acids—the key building blocks of life. Scientists now believe ammonia may not have been present in the Earth's early atmosphere, but updated studies conducted sans ammonia have yielded similar results.


The Double Slit

In 1801, British physicist Thomas Young decided to test whether light is a wave or a stream of particles. He cut two slits in a screen, put a second screen behind it, then shone light through the slits. If light was a stream, it would appear as two dots on the second screen. But if it was a wave, it would spread out as it traversed the slits, creating an interference pattern—a series of light and dark bands—on the second screen. Young observed an interference pattern. More than a century later, researchers found that electrons also create an interference pattern, and concluded that particles can also act like waves.


Bugstunt: Here's a trick that's guaranteed to wow your camping buddies: Listen for a cricket, count the number of chirps the insect makes in 15
seconds, then add 40, and—voil!—you've got the ambient temperature
in degrees Fahrenheit.

Oh, the pesky questions your children ask. Of course you know the answers. Still, here's a refresher.

Q: Why is the sky blue?

The short answer: Because of the way sunlight scatters when it hits the air.

The full answer: The sky appears blue because of a phenomenon known as Rayleigh scattering. When sunlight passes through the atmosphere, the longer yellow, orange and red wavelengths (in the 570-to-700-nanometer range) pass through air molecules virtually unobstructed. But blue (475 nm) and violet (400 nm) light is scattered by air molecules in all directions.


Q: Why is the ocean salty?

The short answer: Because sodium and chloride, the two ingredients in salt, flow into it.

The full answer: Rivers erode sodium-containing rock and carry it out to sea; undersea volcanoes spit up chloride. Sea creatures absorb many of the other minerals found in the ocean, such as calcium and sulfur, but have little use for sodium or chloride, so the salt gets concentrated.


Q: Is it hot in the summer because the Earth is closer to the Sun?

The short answer: No.

The full answer: The Earth is actually farthest from the Sun in July, closest in January. Seasons occur because of the 23.5-degree tilt of Earth's axis. In summer the axis is pointed toward the sun, so days are longer and the energy hitting any one spot is more concentrated.