by Robert Molton; Manuela Amzallag

If you want to go from scrawny to brawny in 30 days, there is no shortage of miracle shape-up programs. But as impressive as beefy pecs and triceps may look, they won’t help you cite the evidence for Einstein’s special theory of relativity, rattle off pi to the 20th decimal place, or liberate yourself from the mass delusion that a penny dropped from the Empire State Building will gather enough speed to kill a hapless pedestrian. We at PopSci believe the body part most worth stretching and toning–not to mention showing off–is the brain. You need to ensure that yours is flexible enough for creative problem solving, strong enough to run the occasional intellectual mini-marathon, and most of all, free of pseudoscientific flab.

You say the brain isn’t really a muscle? Irrelevant. Recent studies indicate that it can bulk up: The hippocampus, a brain region responsible for thought and memory, produces new cells throughout a person’s life, and some neuroscientists believe other parts of the brain also regenerate. The trick to keeping those new neurons? Use ’em or lose ’em. So take our scientific-aptitude quiz, learn the mental muscle groups, and get pumping.


The first step in your regimen is assessment. It’s time to apply
the fat calipers to your gray matter. Gauge your mental conditioning with this PopSci quiz.

target=”popup1″>Click here to take the quiz (this will open a new browser window).


The first lesson from your neurobics instructor: Like any muscle, the brain can be limbered, shaped, and expanded. Here’s a smart workout routine.

Train Your Cranium: Eight activities that build beefier brains.

Competitive Sports

In 2003, University College London researchers found that middle-aged people who regularly engaged in logic and memory games such as cards, bingo and chess performed better on short-term memory, mathematical reasoning and vocabulary tests than those who did not. Animal studies have shown that mentally enriching environments increase the likelihood that new brain cells will survive.


After training rats to cross rope bridges and pencil-wide balance beams, and to master the seesaw, University of Illinois researchers found in a 1990 study that the coordinated rodents’ neurons possessed 25 percent more connections to other brain cells than did those of treadmill-running rats.

Brain Breaks

Duke University neurobiologist Larry Katz suggests getting up from your desk every hour for a change of scenery, even if it’s just a trip to the water cooler. Unfamiliar sensory stimulation can increase the production of brain chemicals called neurotrophins, he says. In a 1996 study, Duke University researchers found that neurotrophins increase the size and complexity of dendrites–the tendrils on a neuron that receive and process information.

Reflex Tuning

In 2003, researchers at Hong Kong’s Chinese University concluded that playing the piano or another instrument significantly improved subjects’ verbal memory. And after studying the leisure activities of almost 500 subjects over the course of 21 years, researchers at New York’s Albert Einstein College of Medicine reported last year that playing a musical instrument is associated with a reduced risk of dementia.

Belly Crunches

“Two hydrogen atoms are walking down the road. One says, ‘I’ve lost an electron.’ ‘You sure?’ the other asks. ‘Yes,’ the first answers, ‘I’m positive.'” Silly joke? Yes, but jokes are not just silly. A 1999 University of Toronto study showed that processing a verbal joke exercises cognitive abilities such as abstract reasoning and the use of long-term memory to reinterpret information in working memory. “If solving math problems in your head is like doing sit-ups, sharing jokes is like playing Frisbee,” explains linguist
David Gamon, coauthor of Building Mental Muscle.

Rest Between Workouts

Many studies suggest that when people fall into rapid-eye-movement (REM) sleep soon after learning something new, they are more likely to retain the new knowledge. And non-REM sleep may give inactive neurons a chance to repair damage caused by free radicals.

Morning Warm-Up

Brush your teeth with the wrong hand. Take a new route to work. “Rarely activated pathways in your brain’s associative network (will be) stimulated, increasing your range of mental flexibility,” says Larry Katz, a Duke University neurobiologist.


Jogging may boost your ability to produce and maintain new brain cells. Researchers at the Salk Institute for Biological Studies reported in 1999 that running doubled the number of new brain cells that survived in adult rodents.


Any trainer will tell you bad technique leaves you vulnerable to
injury. Assess data with a healthy dose of skepticism, or you might pull a conceptual hamstring.

Spot the Junk: Words are powerful. Know how to use them correctly–and how to recognize jargon abuse.

Relative vs. Absolute Risk

In 1995 thousands of women shunned oral contraceptives altogether after a study showed users of a recently introduced form of “the pill” were twice as likely to develop blood clots as were women taking older versions. Yet though the relative risk had indeed doubled, the increase in absolute risk was still tiny: Mortality reportedly climbed from 1.5 to 3 women per million. Meanwhile, in the months following the “pill scare,” pregnancy rates in England and Wales jumped 7 percent over those for the same period the previous year.

Who’s an Expert?

Though a Ph.D. doth a doctor make, it doesn’t always make an expert. Someone with a degree in oceanography is not automatically an authority on other topics. If people were more aware of the distinction, Nobel Prize?winning chemist Linus Pauling might not have gotten so much attention for recommending massive (and, it turns out, unhealthy) doses of vitamin C to treat everything from the common cold to cancer.


A disclaimer appeared in the biology textbooks of Cobb County, Georgia, in 2002: “Evolution is a theory, not a fact, regarding the origin of living things.” In an absolute sense, this is true: Theories are proposed or accepted explanations based on assembled evidence. But in science, many theories–the theory of gravity, for example–enjoy near universal acceptance, based on the preponderance of evidence and the success of the model. The term “theory” does not imply doubts about a phenomenon’s fundamental existence.

Nano-This, Nano-That

The boom in nanotechnology has led to a corresponding boom in nano-babble, rendering the prefix virtually meaningless. Take the recent fad of “nano-reefs” for small home aquariums: If they were actually sized in nano-
meters (billionths of a meter, or 10-9), they’d be invisible to fish and their owners. What’s next, pico-reefs? (Pico: 10-12.)

Nature vs. Nurture

Is human behavior genetically predetermined or is it a result of environmental influences? Dogmatism on both sides of this “debate” has led to innumerable wrong turns, such as social Darwinism on one side and Soviet-era training programs on the other. The correct answer: We are products of both genes and environment, and understanding their complex interactions remains beyond our limited ken.

The Uncertainty Principle

Werner Heisenberg’s uncertainty principle, formulated in 1927, states that a small bit of matter–an electron, for example–cannot have both a well-defined position and a well-defined momentum at the same time. What’s more, measuring one of those properties inexorably disturbs it–you can never know what an electron’s position was before you measured it, because the act of measurement changes its position. Dime-store philosophers have had a field day with this concept, using it to explain all manner of things. Pundits have been known to maintain, for example, that since the presence of a reporter exerts an influence on the people being observed, the journalistic endeavor is an example of the uncertainty principle. But in practice, Heisenberg’s principle only applies to the subatomic world.

Clean Your Filters: Adhere to these basic principles at all times.


In the 1930s Viennese philosopher Karl Popper stated that for a claim to be considered scientific, it must be conceivable to prove it wrong by observation or experiment. For instance, the statement “All elephants are gray” would be falsified by a single sighting of a pink elephant.

Occam’s Razor

When choosing between two competing theories to describe a phenomenon, medieval philosopher William Occam said, the simplest explanation is the best. Sure, maybe dachshunds exist on Earth not because of selective breeding but because aliens brought them here, but why make more assumptions than necessary?

Sample Sufficiency

The smaller the sample size, the less believable the findings. It’s not enough to know that one in 10 study subjects developed adverse reactions to a medication; you must find out how large the pool was. If there were just 10 subjects and one fell ill, the significance is unclear. But if 100 out of 1,000 people got sick, you should avoid that pill.

Paradigm-Shift Principle

Philosopher of science Thomas Kuhn coined the phrase “paradigm shift” to describe rare, profound shifts in the way the world is understood by science: Earth at center of universe, Earth not at center of universe, for example. Paradigm shifts are rare, but use of the phrase to pump up an idea’s importance is frequent. When a theory is trumpeted as revolutionary, part of a paradigm shift, this is usually a red flag for half-baked ideas; be skeptical. Everyday science is more evolutionary than revolutionary; established ideas are upended less often than media reports would have you believe.

Don’t Be a Carrier: Five misconceptions even you (yes, you) have been known to spread.

False: Toilets and bathtubs drain counterclockwise in the Northern Hemisphere, clockwise in the Southern Hemisphere. The Coriolis effect, caused by the rotation of the Earth, can be seen in the spin direction of weather systems such as hurricanes and cyclones. But in the short-lived flush of a toilet, the force
is far too weak to have an impact; the direction of the water’s rotation depends on the toilet’s design.

False: No two snowflakes are alike. Snowflakes are six-sided crystals composed of about 1018 water molecules, giving them unimaginable–but not infinite–potential for variation. In 1988, Nancy Knight, a meteorologist at the National Center for Atmospheric Research, discovered two identical snowflakes that had been collected from clouds above Wisconsin. The snowflakes apparently formed as conjoined twins.

False: Humans use just 10 percent of their brains. MRI and PET scans show that a much larger portion of the brain is engaged
during complex thought processes. And biologists scoff at the idea that we would evolve such an oversize brain–it eats up 19 percent of the fuel in our bloodstream–only to use but a fraction of it.

False: A penny dropped from the Empire State Building would kill someone below. A few calculations tell us that a penny falling edge-on from the 1,050-foot-high observation deck on Floor 86 of the 102-story skyscraper would fall 500 feet before reaching maximum velocity: 57 miles an hour. This is about 1/10 the speed of a low-caliber handgun bullet–fast enough to hurt but, except in freak circumstances, not to kill. It’s a moot point anyway: Thanks to updrafts, coins tossed from the observation deck generally land on the setback roof of Floor 80.

False: The Moon appears larger when it’s on the horizon because it’s magnified by the atmosphere. This is an optical illusion. You can confirm that fact by taking photographs of the Moon as it tracks across the sky: It will appear the same size on the negatives, no matter where it is. The cause of the illusion is the subject of considerable debate, but the leading theory is that it’s a classic Ponzo illusion: The brain mentally magnifies objects near the horizon because it interprets them as far away; thus the Moon appears larger to us when it is closer to the horizon.


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.


Feeling sore and achy? Ready to bag your workout regimen? Wait! These exercises will help you reach your fitness goals with the barest minimum of effort.

Couch Potato Science: Seven movies for the, er, passive learner.

The Fly (1958)

This outlandish story of a human-fly hybrid is not beyond the pale: Scientists have injected multiple human genes into flies to study diseases, and strange “mosaic” creatures have been created, including a sheep-goat with wool and hair interspersed in its coat.

2001: A Space Odyssey (1968)

A team of astrophysicists helped director Stanley Kubrick add gravity to his sci-fi fantasy. The sound of silence is overpowering, as it should be–in the relative vacuum of space, there’s no medium to transmit sounds. And the movie’s space station rotates on its axis, capitalizing on centrifugal force to keep its astronauts’ feet on the floor–an idea first proposed by Russian scientist Konstantin Tsiolkovsky in 1920.

Jaws (1975)

Real sharks don’t hold grudges, and they certainly don’t make repeat assaults on specific boat captains, no matter how crusty. But biologists celebrate Jaws because a bearded Richard Dreyfuss acts and talks like a true scientist, clinical even when contemplating the shredded body of the first victim: “It indicates the non-frenzied feeding of a large Squalus, possibly longimanus or Isurus glaucus …”

Boys from Brazil (1978)

This sci-fi classic, featuring an army of Hitler copies, paints a remarkably accurate picture of cloning methods for the time. A hitch: Just because the clones are genetically identical to Hitler doesn’t mean they’ll act like him.

Contact (1997)

Based on the book by Carl Sagan, this film hews reasonably to fact. At Sagan’s request, astrophysicist Kip Thorne conceived the story’s greatest
conceptual leap: Ellie Arroway’s 18-hour, 26-light-year wormhole journey to Vega. Thorne then published a Contact-inspired paper about these
theoretical tunnels in space-time in the prestigious journal
Physical Review Letters.

Gattaca (1997)

This futuristic vision of genetic segregation is both far-out and near at hand. Already, human embryos that are created in the lab can be scanned for genetic defects so that only healthy ones will be implanted in the mother’s womb. But it’ll be years before we can build security systems that grant or deny entry based on an instantaneous DNA test.

Titanic (1997)

OK, so Leo’s motor skills are impossibly intact after sloshing through a ship full of ice water. But director James Cameron compensates for that with near-perfect physics in his depiction of the sinking vessel. Realistically, gravity’s downward force is barely larger than the upward-acting buoyancy of trapped air pockets, causing a gentle descent, not the typical Hollywood maelstrom.

Mnemonics: The cheater’s guide to scientific erudition.

My Very Easy Method: Just Set Up Nine Planets

The first letter of each planet’s name, in increasing distance from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.


From this alternate spelling of a favorite liqueur, the six elemental building blocks of life: carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur.

Roy G. Biv

The name of this nonexistent person holds the first letter of each color in the visible spectrum, in order: red, orange, yellow, green, blue, indigo, violet.

Oh, Be a Fine Girl, Kiss Me!

The first letters of these words provide the stellar classifications, from ultrahot O stars to cool M stars. More PC version: Oh, Be a Fine Guy, Kiss Me! Better yet: Only Boys Accepting Feminism Get Kissed Meaningfully.

Sir, I send a rhyme excelling / In sacred truth and rigid spelling / Numerical sprites elucidate / For me the lexicon’s dull eight

Encoded in second-rate poetry: the transcendental number pi to 20 places. Just count the number of letters in each word: three, one, four, one, five, nine …

Brainfood? U.S. consumers spent more than $210 million on supposed brain-boosting supplements in 2002. Ginkgo biloba:$130 million; Multivitamins: $33 million; Combination herbs: $22 million; Plant and fish oils: $14 million; Other single herbs: $12 million. Source: Nutrition Business Journal

**Science: The Cliffs Notes

How to fake it when the conversation goes over your head.**

Subject: Time Travel

What to say: “I think Stephen Hawking’s chronology protection conjecture is dead on.”

What you just said: Time travel into the past isn’t impossible according to classical physics and the general theory of relativity, but Hawking proposed that quantum-level effects conspire to always prevent it and its associated paradoxes. His most famous science-fiction-writer-befuddling question: If time travel is possible, why haven’t we been overrun by tourists from the future?

Subject: Superstring Theory

What to say: “The problem is, no one’s ever seen a supersymmetric particle.”

What you just said: Superstring theory–the leading candidate for a “theory of everything” that can describe gravity, electromagnetism and the strong and weak forces with a single set of rules–posits the existence of a slew of undiscovered “supersymmetric” particles, such as selectrons and squarks. But physicists still haven’t seen evidence of them.

Subject: Expanding Universe

What to say: “Isn’t it wonderful that after all these years, Einstein’s greatest mistake may not have been so great?”

What you just said: Straining to balance equations in his relativity theory, Einstein decided in 1917 that an unknown cosmological force was counteracting gravity–an idea he later called his greatest blunder. Then in 1998, two studies showed that the universe is accelerating–and hence that some new force (now called dark energy) must indeed be acting against gravity.

Subject: Tachyons

What to say: “But wouldn’t tachyons violate causality?”

What you just said: This putative class of faster-than-light particles has never been observed experimentally, but physicists keep looking. And there’s another problem: According to special relativity, tachyons would turn time on its head. If you used tachyons to send a message from Point A to Point B, certain observers would see the message being received before it had been sent. Effect would precede cause: a violation of causality.

Subject: Human Genome Project

What to say: “30,000 genes can’t be enough to generate the complexity of a human being.”

What you just said: Before the Human Genome Project published maps of the human genome in early 2001, researchers expected that the full complement of human DNA would contain as many as 100,000 genes. The surprise figure–roughly 30,000–means that humans possess only slightly more genes than the lowly wall cress plant (25,000).

The Basic Web: Where to turn on the Net for scientific bolstering.

_howstuffworks.com_: A great basic resource for everything from car engines to CAT scans. This physics reference covers everything from quarks to kinetic energy. But the real gem is the Crackpot Index, useful for evaluating “revolutionary” physics.

_nap.edu_: Dull? Perhaps. But with browsable online editions of more than 3,000 books from the National Academy of Sciences and its ilk, this is a dense Web cluster of trustworthy science.

_quackwatch.org_: Dedicated to fighting medical frauds, Quackwatch identifies misleading health information on the Internet–and provides a handy, seven-step method for spotting bogus science.

_scienceworld.wolfram.com_: The self-proclaimed “best resource for math and science” on the Internet is a simple and reliable quick-reference guide that doesn’t gloss over details.

_wikipedia.org_: Collaborative, open-source Wikipedia is the encyclopedia equivalent of a peer-reviewed journal–except that anyone can post a definition, or correct an existing posting.


Before you got fit, you wouldn’t have dared meet geeks and
eggheads on their own turf. Now these are your people. So
chat, flirt, and don’t forget to flex.

Top Nerd Bars: Science abs pumped? Here’s where to show them off.

Miracle of Science, Cambridge, MA

Geek Factor: Harvard and MIT profs and local biotech workers lounge at fireslate tables surrounded by microscopes and other lab paraphernalia. A giant, wall-mounted menu is modeled after the periodic table of elements.

Guaranteed Pick-Up Line: “Want to experiment with coupled-wave theory?”

Outpost Tavern, Houston, TX

Geek Factor: Johnson Space Center astronauts have been knocking back brews here for more than 20 years. Every April 12 is Yuri’s Night–celebrating cosmonaut Gagarin’s historic jaunt into space.

Guaranteed Pick-Up Line: “Ever wonder what Earth looks like from the back of a Ford Explorer?”

Amigo’s, Pasadena, CA

Geek Factor: Every other Wednesday is Quantum Margarita Night, when physicists from Caltech and NASA’s Jet Propulsion Lab meet to drink strawberry margaritas and talk shop.

Guaranteed Pick-Up Line: “What’s a nice girl like you doing in an n-dimensional space like this?”

DNA Lounge, San Francisco, CA

Geek Factor: A “no Microsoft zone,” this dance club equipped with Linux-based Internet kiosks and live webcasts offers its source code to patrons for free.

Guaranteed Pick-Up Line: “Every now and then two numbers meet, link, and become forever binary.”

Celtic Bayou, Redmond, WA

Geek Factor: This Irish pub features a wireless network and lunch discounts for Microsoft employees.

Guaranteed Pick-Up Line: “Hey, nice GUI. Want to integrate our matrices?”

Sci-Fi Cafe, New Haven, CT

Geek Factor: Yalies meet here to sip Hale-Bopps (a nonalcoholic mix of cranberry, orange and lime juices) or Saturn Hemisphere martinis.

Guaranteed Pick-Up Line: “If you were a phaser, you’d be set on ‘stunning.'”

Koa House Grill, Kamuela, HI

Geek Factor: The Koa House is so close to the W.M. Keck Observatory that local astronomers refer to its lounge as the Koa boardroom.

Guaranteed Pick-Up Line: “I’ve heard Uranus rotates on its side. True?”

Barstool Science: Three tricks to make you the life of the nerd party.

Mbius Strip

Mark the bottom-right and top-left corners of a long, thin strip of paper with X’s, and the other two corners with O’s. Twist and roll the paper such that X meets X and O meets O, and tape the ends together. Ask the drunk next to you how many sides this strip has. If he says two, draw a line along the middle of the strip until you’re back where you started to show him that a Mbius strip is one-sided. Now punch a hole in the strip and ask: “If there’s only one side, where does the hole lead?” Raise your eyebrows meaningfully. The science: Welcome to the weird mathematical field of topology. The hole in the strip suggests how wormholes–hypothetical shortcuts between distant points in the universe–could work.

Floating Needle

Using a couple of toothpicks, lower a steel sewing needle (brought from home) onto the surface of a bowl of water. It will stay on top thanks to surface tension, the huddling together of polarized water molecules due to hydrogen bonding. Next, get some powdered soap from the bathroom, sprinkle it into the bowl, and watch the needle sink to the bottom. The science: Soap has
an electrically charged carboxylic-acid structure at one end of each molecule. These structures vigorously attract water molecules, pulling them from their mutual attractions and thereby breaking the surface tension.

Lemon Battery

Grab a penny, bum a lemon from the bartender, and wrassle up a galvanized nail and some copper wire. Squeeze the lemon until it’s soft, then make two small cuts. Insert the nail and penny in the holes, attaching separate lengths of wire to each. Make the guy next to you touch his tongue to the free ends of the wire. It’ll tingle. The science: In this makeshift voltaic battery, the zinc-coated nail is the negative electrode and the copper-coated penny the positive. The electrolyte is lemon juice, whose positively charged hydrogen ions react with zinc: Zn + 2H+ -> Zn2+ + H2. The penny helps channel electrons through the circuit and your neighbor’s tingly tongue.