10 Scientific Laws and Theories You Really Should Know

Whether we're launching a space shuttle or trying to discover another Earth-like planet, we rely on scientific laws and theories to guide us.

Photo courtesy NASA/Sandy Joseph, Robert Murray

by Jacob Silverman
Scientists have many tools available to them when attempting to describe how nature and the universe at large work. Often they reach for laws and theories first. What's the difference? A scientific lawcan often be reduced to a mathematical statement, such as E = mc²; it's a specific statement based on empirical data, and its truth is generally confined to a certain set of conditions. For example, in the case of E = mc², c refers to the speed of light in a vacuum.

A scientific theory often seeks to synthesize a body of evidence or observations of particular phenomena. It's generally -- though by no means always -- a grander, testable statement about how nature operates. You can't necessarily reduce a scientific theory to a pithy statement or equation, but it does represent something fundamental about how nature works.

Both laws and theories depend on basic elements of the scientific method, such as generating a hypothesis, testing that premise, finding (or not finding) empirical evidence and coming up with conclusions. Eventually, other scientists must be able to replicate the results if the experiment is destined to become the basis for a widely accepted law or theory.

In this article, we'll look at 10 scientific laws and theories that you might want to brush up on, even if you don't find yourself, say, operating a scanning electron microscope all that frequently. We'll start off with a bang and move on to the basic laws of the universe, before hitting evolution. Finally, we'll tackle some headier material, delving into the realm of quantum physics.

The big bang theory

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10: Big Bang Theory

If you're going to know one scientific theory, make it the one that explains how the universe arrived at its present state. Based on research performed by Edwin Hubble, Georges Lemaitre and Albert Einstein, among others, the big bang theory postulates that the universe began almost 14 billion years ago with a massive expansion event. At the time, the universe was confined to a single point, encompassing all of the universe's matter. That original movement continues today, as the universe keeps expanding outward.

The theory of the big bang gained widespread support in the scientific community after Arno Penzias and Robert Wilson discovered cosmic microwave background radiation in 1965. Using radio telescopes, the two astronomers detected cosmic noise, or static, that didn't dissipate over time. Collaborating with Princeton researcher Robert Dicke, the pair confirmed Dicke's hypothesis that the original big bang left behind low-level radiation detectable throughout the universe.

Hubble and his famous law helped to quantify the movement of the universe's galaxies.

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9: Hubble's Law of Cosmic Expansion

Let's stick with Edwin Hubble for a second. While the 1920s roared past and the Great Depression limped by, Hubble was performing groundbreaking astronomical research. Hubble not only proved that there were other galaxies besides theMilky Way, he also discovered that these galaxies were zipping away from our own, a motion he called recession.

In order to quantify the velocity of this galactic movement, Hubble proposed Hubble's Law of Cosmic Expansion, aka Hubble's law, an equation that states: velocity = H₀ ×distance. Velocity represents the galaxy's recessional velocity; H₀ is the Hubble constant, or parameter that indicates the rate at which the universe is expanding; and distance is the galaxy's distance from the one with which it's being compared.

Hubble's constant has been calculated at different values over time, but the current accepted value is 70 kilometers/second per megaparsec, the latter being a unit of distance in intergalactic space [source:White]. For our purposes, that's not so important. What matters most is that Hubble's law provides a concise method for measuring a galaxy's velocity in relation to our own. And perhaps most significantly, the law established that the universe is made up of many galaxies, whose movements trace back to the big bang.

Kepler's law of areas

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8: Kepler's Laws of Planetary Motion

For centuries, scientists battled with one another and with religious leaders about the planets' orbits, especially about whether they orbited our sun. In the 16th century, Copernicus put forth his controversial concept of a heliocentric solar system, in which the planets revolved around the sun -- not the Earth. But it would take Johannes Kepler, building on work performed by Tyco Brahe and others, to establish a clear scientific foundation for the planets' movements.

Kepler's three laws of planetary motion -- formed in the early 17th century -- describe how planets orbit the sun. The first law, sometimes called the law of orbits, states that planets orbit the sun elliptically. The second law, the law of areas, states that a line connecting a planet to the sun covers an equal area over equal periods of time. In other words, if you're measuring the area created by drawing a line from the Earth to the sun and tracking the Earth's movement over 30 days, the area will be the same no matter where the Earth is in its orbit when measurements begin.

The third one, the law of periods, allows us to establish a clear relationship between a planet's orbital period and its distance from the sun. Thanks to this law, we know that a planet relatively close to the sun, like Venus, has a far briefer orbital period than a distant planet, such as Neptune.

Thanks to Newton's universal law, we can figure out the gravitational force between any two objects.

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7: Universal Law of Gravitation

We may take it for granted now, but more than 300 years ago Sir Isaac Newton proposed a revolutionary idea: that any two objects, no matter their mass, exert gravitational force toward one another. This law is represented by an equation that many high schoolers encounter in physics class. It goes as follows:

F = G × [(m1m2)/r²]

F = G × [(m₁m₂)/r²]

F is the gravitational force between the two objects, measured in Newtons. M₁ and m₂ are the masses of the two objects, while r is the distance between them.G is the gravitational constant, a number currently calculated to be 6.672 × 10-¹¹ N m² kg^-2 [source:Weisstein].

The benefit of the universal law of gravitation is that it allows us to calculate the gravitational pull between any two objects. This ability is especially useful when scientists are, say, planning to put a satellite in orbit or charting the course of the moon.

Newton's second law of motion

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6: Newton's Laws of Motion

As long as we're talking about one of the greatest scientists who ever lived, let's move on to Newton's other famous laws. His three laws of motion form an essential component of modern physics. And like many scientific laws, they're rather elegant in their simplicity.

The first of the three laws states an object in motion stays in motion unless acted upon by an outside force. For a ball rolling across the floor, that outside force could be the friction between the ball and the floor, or it could be the toddler that kicks the ball in another direction.

The second law establishes a connection between an object's mass (m) and its acceleration (a), in the form of the equation F = m × a. F represents force, measured in Newtons. It's also a vector, meaning it has a directional component. Owing to its acceleration, that ball rolling across the floor has a particular vector, a direction in which it's traveling, and it's accounted for in calculating its force.

The third law is rather pithy and should be familiar to you: For every action there is an equal and opposite reaction. That is, for every force applied to an object or surface, that object pushes back with equal force.

The laws of thermodynamics in action

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5: Laws of Thermodynamics

The British physicist and novelist C.P. Snow once said that a nonscientist who didn't know the second law of thermodynamics was like a scientist who had never read Shakespeare [source: Lambert]. Snow's now-famous statement was meant to emphasize both the importance of thermodynamics and the necessity for nonscientists to learn about it.

Thermodynamics is the study of how energy works in a system, whether it's an engine or the Earth's core. It can be reduced to several basic laws, which Snow cleverly summed up as follows [source: Physics Planet]:

• You can't win.
• You can't break even.
• You can't quit the game.

Let's unpack these a bit. By saying you can't win, Snow meant that since matter and energy are conserved, you can't get one without giving up some of the other (i.e., E=mc²). It also means that for an engine to produce work, you have to supply heat, although in anything other than a perfectly closed system, some heat is inevitably lost to the outside world, which then leads to the second law.

The second statement -- you can't break even -- means that due to ever-increasing entropy, you can't return to the same energy state. Energy concentrated in one place will always flow to places of lower concentration.

Finally, the third law -- you can't quit the game -- refers to absolute zero, the lowest theoretical temperature possible, measured at zero Kelvin or (minus 273.15 degrees Celsius and minus 459.67 degrees Fahrenheit). When a system reaches absolute zero, molecules stop all movement, meaning that there is no kinetic energy, and entropy reaches its lowest possible value. But in the real world, even in the recesses of space, reaching absolutely zero is impossible -- you can only get very close to it.

Buoyancy keeps everything from rubber ducks to ocean liners afloat.

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4: Archimedes' Buoyancy Principle

After he discovered his principle of buoyancy, the ancient Greek scholar Archimedes allegedly yelled out "Eureka!" and ran naked through the city of Syracuse. The discovery was that important. The story goes that Archimedes made his great breakthrough when he noticed the water rise as he got into the tub [source: Quake].

According to Archimedes' buoyancy principle, the force acting on, or buoying, a submerged or partially submerged object equals the weight of the liquid that the object displaces. This sort of principle has an immense range of applications and is essential to calculations of density, as well as designing submarines and other oceangoing vessels.

A hypothetical (and simplified) example of how natural selection might play out amongst frogs

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3: Evolution and Natural Selection

Now that we've established some of the fundamental concepts of how our universe began and how physics play out in our daily lives, let's turn our attention to the human form and how we got to be the way we are. According to most scientists, all life on Earth has a common ancestor. But in order to produce the immense amount of difference among all living organisms, certain ones had to evolve into distinct species.

In a basic sense, this differentiation occurred through evolution, through descent with modification [source: UCMP].Populations of organisms developed different traits, through mechanisms such as mutation. Those with traits that were more beneficial to survival such as, a frog whose brown coloring allows it to be camouflaged in a swamp, were naturally selected for survival; hence the term natural selection.

It's possible to expand upon both of these theories at greater length, but this is the basic, and groundbreaking, discovery that Darwin made in the 19th century: that evolution through natural selection accounts for the tremendous diversity of life on Earth.

Einstein's theory of general relativity changed our understanding of the universe.

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2: Theory of General Relativity

Albert Einstein's theory of general relativity remains an important and essential discovery because it permanently altered how we look at the universe. Einstein's major breakthrough was to say that space and time are not absolutes and that gravity is not simply a force applied to an object or mass. Rather, the gravity associated with any mass curves the very space and time (often called space-time) around it.

To conceptualize this, imagine you're traveling across theEarth in a straight line, heading east. After a while, if someone were to pinpoint your position on a map, you'd actually be both east and far south of your original position. That's because the Earth is curved. To travel directly east, you'd have to take into account the shape of the Earth and angle yourself slightly north. (Think about the difference between a flat paper map and a spherical globe.)

Space is pretty much the same. For example, to the occupants of the shuttle orbiting the Earth, it can look like they're traveling on a straight line through space. In reality, the space-time around them is being curved by the Earth's gravity (as it would be with any large object with immense gravity such as a planet or a black hole), causing them to both move forward and to appear to orbit the Earth.

Einstein's theory had tremendous implications for the future of astrophysics and cosmology. It explained a minor, unexpected anomaly in Mercury's orbit, showed how starlight bends and laid the theoretical foundations for black holes.

Is it a particle, a wave or both?

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1: Heisenberg's Uncertainty Principle

Einstein's broader theory of relativity told us more about how the universe works and helped to lay the foundation for quantum physics, but it also introduced more confusion into theoretical science. In 1927, this sense that the universe's laws were, in some contexts, flexible, led to a groundbreaking discovery by the German scientist Werner Heisenberg.

In postulating his Uncertainty Principle, Heisenberg realized that it was impossible to simultaneously know, with a high level of precision, two properties of a particle. In other words, you can know the position of an electron with a high degree of certainty, but not its momentum and vice versa.

Niels Bohr later made a discovery that helps to explain Heisenberg's principle. Bohr found that an electron has the qualities of both a particle and a wave, a concept known as wave-particle duality, which has become a cornerstone of quantum physics. So when we measure an electron's position, we are treating it as a particle at a specific point in space, with an uncertain wavelength. When we measure its momentum, we are treating it as a wave, meaning we can know the amplitude of its wavelength but not its location.

Keep reading for more science stuff you might like.

Silverman, Jacob.  "10 Scientific Laws and Theories You Really Should Know"  19 January 2011.  HowStuffWorks.com. <http://science.howstuffworks.com/innovation/scientific-experiments/10-scientific-laws-theories.htm>  05 June 2012.

How the Sony Smartwatch Works

by Patrick Kiger

Amazing Timepieces Image Gallery

One of the early computer/calculator/watches to be produced

Keystone/Hulton Archive/Getty Images

It's strange to think that something once as ubiquitous as the wristwatch is now an endangered species, rendered unnecessary by the clock display on mobile phones. According to the consumer research firm Experian Simmons, just 42 million Americans bought a watch for themselves in 2011, down from 55 million in 2004 [source:Goetz]. In the UK, a recent study showed that 14 percent of the public -- and 28 percent of those between ages 15 and 24 -- saw no need for a timepiece around their wrist anymore [source: McFarlane].

So, faced with becoming little more than a dusty museum piece, perhaps it was inevitable that watches -- like phones, coffee makers, refrigerators, automobiles and even entire houses -- would become "smart," i.e., equipped withmicroprocessors, software and wireless connections that allow them to perform all sorts of functions beyond the one for which they originally were intended.

It's unclear who first came up with the idea of turning the watch into a tiny computer with communications and networking capabilities. In the late 1990s, Swiss watchmaker Swatch and Dutch electronics giant Phillips tested a watch equipped with a radio-frequency identification chip that enabled it to pay subway fares and ski-lift fees [source: Taggart]. One of the first multi-featured devices may have been a wristwatch-sized computer equipped with both a touchscreen and a microphone for voice-activated apps and communicating, developed by Chandra Narayanaswami of IBM back in 2000 [source: Eisenberg]. In 2003, watchmaker Fossil, Microsoft and handheld computer maker Palm teamed up to develop the SPOT (Smart Personal Objects Technology) watch, a device equipped to wirelessly receive stock quotes, send and receive instant messages and do other stuff that seemed utterly cool at the time [source: McHugh].

Since then, we've seen the advent of vastly more powerful, sophisticated smart watches. One of the newest, the $149 Sony SmartWatch, is designed to do a lot of the things you count on your smartphone to do, such as accessing your digital music collection and keeping you plugged in to social networks. Better yet, it can do those things without requiring you to reach into your pocket or dig through your purse -- which may be one big advantage that wristwatches still have over phones [source: Sony.com].

What makes the Sony SmartWatch smart?

With its touchscreen display and icons, the Sony SmartWatch looks a lot like a really, really small Android smartphone. It's just 1.42 inches by 1.42 inches (3.6 by 3.6 centimeters) across, 0.3 inches (0.7 centimeters) in thickness, and weighs 0.55 ounces (15.5 grams) (somewhat less than the band to which it's attached) [source: Sony.com].

But while the SmartWatch lacks heft, it also demonstrates just how far the state of the art in miniaturization has come. While Sony doesn't disclose much about the hardware inside, the gadget-hacking Web site CMW, which dismantled one of the watches, reports that it sports a CPU that runs at 120 MHz, 128 kilobytes of RAM, and a full megabyte of flash memory for storage [sources: Murph, CMW]. That's more electronic muscle than some laptop computers had a couple of decades ago, and it enables the SmartWatch to run a stripped-down operating system that's compatible with Google's Android OS for phones, release 2.1 and up [source: Sony].

That last part is crucial, because when you aren't using the SmartWatch to check the time, it essentially functions as a Bluetooth-equipped peripheral add-on to your Android phone, piggybacking on the latter's wireless Internet connection. For some functions, such as music, it acts like a remote control, sifting through the phone's multiple gigabytes of storage to select and play songs. When the phone rings, you also can use the watch face to check who's calling you, and then -- provided you're also wearing a Bluetooth earpiece and microphone -- you can even answer the call without taking the phone out of your pocket or handbag [source: Olivarez-Giles].

But that's not the really sexy stuff. The SmartWatch can run its own teeny-weeny apps from Google's Play store or Sony LiveWare as well [source: Bennett]. Those enable you to scan your e-mail inbox, read texts, Tweets and Facebook posts, and even check the weather [source: Olivarez-Giles]. You can scroll through the apps by swiping a finger from right to left, while swiping downward eventually also gets you into an app tray similar to the one on Android phones [source: Bennett].

Fitness trainers demonstrate Motorola's MotoACTV at the 2012 International Consumer Electronics Show in Las Vegas.

David Becker/Getty Images

SmartWatch Pros, Cons and Competition

It should be mentioned that Sony isn't the only manufacturer vying to replace your watch with a multi-function gadget that'll enable you to lead a totally, continually connected wireless lifestyle. There's also the Motorola MotoACTV, which is not only designed to augment Motorola's RAZR phones, but also enables you to monitor your heart rate and check your route with a GPS chip while running or cycling [source: Oliver]. And there's also upstart tech company Allerta's new Pebble, which is so trendy that its development was partly funded by $4.7 million obtained through the crowd micro-financing site Kickstarter [source: Kim]. Unlike the Sony SmartWatch, the Pebble is designed to work with both iPhones and Android phones [source: Rieland].

So, how does the SmartWatch stack up against the competition? According to CNET reviewer Brian Barrett, the device has both strong and weak points. Its miniscule size makes it a lot more portable and less obtrusive than the bulkier MotoACTV, and the elegant design and variety of stylish colored wristbands available make the SmartWatch into a nice fashion accessory. But while Barrett was easily able to download and install apps, he found that some of them were glitch-ridden, and either didn't fully work or caused the watch to crash and reboot. The SmartWatch's battery life was another downside, since it's way shorter than a conventional watch. Barrett found that he needed to recharge it at least every two days, not even close to Sony's claimed longevity of four days [source: Barrett].

Slashgear reviewer Chris Davies noted that the SmartWatch, like other smart watches, also has a key limitation: Unlike a smartphone, its tiny screen is too small to tap out responses to your social media stream, e-mail and texts, which downsizes your interactions into one-sided communication [source:Davies]. Great for those texts you'd rather not respond to. Not so great for the ones that warrant a note back.

Kiger, Patrick.  "How the Sony Smartwatch Works"  29 May 2012.  HowStuffWorks.com. <http://electronics.howstuffworks.com/gadgets/clocks-watches/sony-smartwatch.htm>  05 June 2012.

10 Most Expensive Classic Cars

Image Gallery: Classic Cars

This 1962 Ferrari was presented during an auction for 33 of world's most significant sport and racing Ferrari cars at the Ferrari's headquarters in Fiorano, Italy, in 2007. See more pictures of classic cars.

AP Photo/Luca Bruno

by Patrick E. George

Automotive aficionados know that are cars, and then there are "cars."

There are the cars we drive to work every day, the cars we use to take our kids to school, the cars we pick up groceries with and the ones we use to haul stuff from The Home Depot. They're utilitarian, reliable, practical and in most cases, they're relatively boring, too.

But others are the rare automobiles that provide more than just transportation. They're the ones that border on rolling art. The cars that most consider to be miracles of engineering. The ones that glorify speed and luxury. The ones that are best described as madness sitting on four rubber tires.

As long as people have been driving, cars like these have existed. Some individual or some company has always been there to push the envelope, to ask, "How much faster can we make this? How much better can it be?" Every era of automotive history has its legends. They have names like Bentley, Bugatti and Ferrari.

Many of them were made in extremely limited numbers during their time, and of those few, many became lost to history. A rare handful (or fewer) are still around, flaunting record-breaking speed and handling from a time long since past.

They can be yours, too -- if you've got the cash. The average person would never even consider spending $100,000 on a car. So what would make a person spend several million dollars on a car?

You're about to find out. In this article, we'll look at the most recent list of the world's 10 most expensive classic cars, the history behind them and how much of a financial hit their new owners' wallets took just to put them in their garages

A view of the Ferrari logo at the luxury and racing automaker's 60th anniversary celebrations at the headquarters Fiorano race track, in Maranello central Italy.

AP Photo/Luigi Vasini

10: 1962 Ferrari 250 LM

Car: 1962 Ferrari 250 LM

Number produced: 32

Price at auction: $6.9 million

By the 1960s, Ferrari could tell that racing was moving away from front-engine layouts and towards mid-engine cars. They tried to capitalize on this with the 250 LM. The 250 engine from the Testa Rossa was mounted in the middle of the car to create a new type of racer. It was a production version of the company's 250 P prototype car.

Designed by Pininfarina, it was built to be a GT racer, but the FIA had other plans. The racing body insisted Ferrari would never build 100 examples of the 250 LM to allow it to qualify for GT racing. And they were right -- only 32 of the cars were ever built. This limited the 250 LM to racing in the prototype class, not full-blown GT racing, something that allowed the American-built Shelby to dominate racing [source: Ultimate Car Page].

The car was still successful at racing, securing Ferrari's last victory at Le Mans to this day. Because so few were ever produced, it is considered highly valuable among collectors. At a 2008 auction, it secured a price tag of $6.9 million.

A 1965 Shelby Daytona Cobra Coupe

AP Photo/Mary Altaffer

9: 1965 Shelby Daytona Cobra Coupe

Car: 1965 Shelby Daytona Cobra Coupe

Number produced: 6

Price at auction: $7.25 million

Shelby Cobra. Those two words hardly need an introduction, but the Shelby Daytona Cobra Coupe has a fascinating history, one born out of America's desire to break into the European-dominated world of GT racing.

Shelby and Ferrari were engaged in an epic racing rivalry in the 1960s, one that pitted the Texan Shelby'shot-rod tuners against Italy's motoring aristocracy. Ferrari was dominating the F.I.A. World Manufacturers Championship GT class, but Shelby wanted to knock it off its pedestal.

They built the iconic blue-and-white coupe version of the Cobra, which featured a snarling Ford 289 cubic-inch V8. And win it did: The Daytona Cobra Coupe became the only American car to beat a Ferrari in world championship racing in Europe.

The fourth of the six coupes was auctioned off in 2009, and it earned $7.25 million on the block. That still holds the record for the highest price paid for an American car at a public auction [source: Mecum].

The world's oldest surviving Rolls-Royce

AP Photo/Kirsty Wigglesworth

8: 1904 Rolls-Royce 10 HP

Car: 1904 Rolls-Royce 10 HP

Number produced: 17

Price at auction: $7.3 million

It's hard to image a time in automotive history when some car engines only produced 10 horsepower, but at the dawn of the 20th century, it was enough to get the job done. Two companies, Rolls and Royce, teamed up to build 17 of these early automobiles. A humble 1.8-liter twin-cylinder engine powered the cars. It follows the early tradition of looking like a horse-drawn carriage with a steering wheel -- and no place for a horse. It has big, brass headlamps, wooden spoke wheels and a horn that looks like a musical instrument.

The car sold at auction for $7.3 million in 2004 and is the oldest known Rolls Royce in existence. Its chassis (number 20154) was updated in the 1930s but later restored to its original specification in the 1950s. It had been squirreled away in a farm building, perhaps to hide it from a foreign enemy, as was the case with many pre-World War II vehicles [source: Supercars.net].

While 10 horsepower may not be a lot, it doesn't in any way diminish this Rolls Royce's place in history.

The logo of Mercedes-Benz is seen on a wheel rim of a Mercedes-Benz model at the production site in Sindelfingen, Germany.

AP Photo/Thomas Kienzle

7: 1929 Mercedes-Benz 38/250 SSK

Car: 1929 Mercedes-Benz 38/250 SSK

Number produced: 30-35

Price at auction: $7.4 million

This particular Mercedes-Benz has an interesting history. Shorter and smaller than many of the massively long performance cars of its day (some of which made this list), the SSK stands for Super Sport Kurz -- German for short.

It was the last car Ferdinand Porsche designed for Mercedes-Benz before he left the company to build his own cars. It may have been small, but its engine was mighty -- a 7.1-liter supercharged powerplant.

In 1941, an English gentleman and prolific car collector named George Milligen became this car's 11th owner. Milligen kept the car until his death at the age of 94. Amazingly, the car was never restored and featured nearly all its original parts -- only the sump was replaced in 75 years of ownership [source: Speed TV]. Now that's taking care of your car!

At a 2004 auction, Milligen's Mercedes fetched $7.4 million. Let's hope its new owner maintains it just as well.

The badge on an extremely rare 1937 Bugatti Type 57S Atalante is seen at Phoenix Green garage in Hartley Wintney, in Hampshire, England.

AP Photo/Kirsty Wigglesworth

6: 1937 Bugatti Type 57SC Atalante

Car: 1937 Bugatti Type 57SC Atalante

Number produced: 11

Price at auction: $7.9 million

Bugatti's incredible automobiles saw a lot of success in racing, but it made some amazing road-going cars as well. One of the most sought-after examples is the Type 57SC Atalante, a highly unusual car with a swooping roof and fenders and riveted body panels. Fewer than a dozen were made, and no two were built exactly alike.

The SC was the ultimate iteration of the Type 57 line. It had a supercharged 3.3-liter straight-eight cylinder engine putting out 170horsepower. Also, the SC had an upgraded chassis compared to other Type 57s for better handling and balance. Some have even described it as the world's first supercar [source: Supercars.net].

At the Pebble Beach Concours d'Elegance in 2008, one example of the 57SC went for close to $8 million at auction.

A Mercedes-Benz logo casts a shadow

AP Photo/Kamran Jebreili

5: 1937 Mercedes-Benz 540K Special Roadster

Car: 1937 Mercedes-Benz 540K Special Roadster

Number produced: 26

Price at auction: $8.2 million

Karl Benz invented the gasoline-powered automobile, and since then, Mercedes-Benz has always been known as a company at the pinnacle of engineering. This has been true throughout its long history, and it has led the company to produce some truly stunning cars.

The 540K Special Roadster was no exception. The 17-foot-long (5.2-meter), two-seat convertible features classic pre-war styling including swooping fenders, big headlights and a tire mounted on the trunk. It was massive and it was exclusive -- just 26 Special Roadsters were built, intended only for Europe's political and financial elite. The 540K featured a 5.4-liter straight-eight cylinder engine with 180 horsepower, thanks to its Roots-type supercharger -- hence the K, which stands for "Kompressor" [source: RM Auctions].

This car was owned by an Englishman who bought it in 1937, then managed to squirrel it away during the war. Driving such an ostentatious German car probably wouldn't have gone over too well with the neighbors, right? The car went through several owners, the last one being Formula 1 chief Bernie Ecclestone, until it was sold at auction for $8.2 million.

This 1962 Ferrari 330 TRI is part of a collection of dream cars and memorabilia to be sold at the legendary home of Ferrari in Maranello, Italy.

AP Photo/Luca Bruno

4: 1962 Ferrari 330 TRI/LM

Car: 1962 Ferrari 330 TRI/LM

Number produced: 1

Price at auction: $9.3 million

The last two letters in this Ferrari's name are LM, which stand for Le Mans, as in The 24 hours of Le Mans. The day-long race is the world's oldest endurance race and one of the most difficult in motorsports. It's also a race to which Ferrari is no stranger.

The final and ultimate evolution of the Testa Rossa line, the 330 TRI/LM won the 1962 Le Mans race while being driven by Phil Hill and Olivier Gendebien. It features a 4-liter V-12 with nearly 400 horsepower, and it's the last front-engine racing car built by Ferrari as well as the last front-engine car to win at Le Mans. Many consider it to be the greatest and final example of the golden age of front-engine racing [source: RM Auction].

Chassis number 0808 went for $9.3 million at a Sotheby's auction.

The sign of the traditional Italian company Bugatti is seen on an old timer in the museum in Munich, Germany.

AP Photo/Camay Sungu

3: 1931 Bugatti Type 41 Royale Kellner

Car: 1931 Bugatti Type 41 Royale Kellner

Number produced: 6

Price at auction: $9.8 million

During the first half of the 20th Century, a French company named Bugatti made some of the most exclusive, expensive, luxury-laden and fastest automobiles on the planet. Designed by the eccentric Italian engineer Ettore Bugatti, their cars featured light bodies, huge engines and exotic styling. Like a lot of European car companies, however, they weren't able to survive World War II.

Bugattis were often exercises in automotive insanity, and the 1931 Type 41 Royale Kellner was no exception. The car featured a massive 12.7-liter straight-eight engine, one which remains the largest engine ever put in a privately-sold automobile. The rest of it was big, too -- the wheelbase was more than 15 feet (4.6 meters) in length, and its price tag was far beyond the buyers of the Great Depression era when it was built [source: Forbes].

Only six were constructed, and this one was hidden behind a false wall to save it from the raging war in Europe. In 1987 it was sold at auction for nearly $10 million.

Today, the Volkswagen Group has revived the Bugatti marque and built the record-breaking Veyron, a car capable of speeds of more than 250 miles per hour (402.3 kilometers per hour). The insanity lives on.

The Ferrari prancing horse logo

AP Photo/Marco Vasini

2: 1961 Ferrari 250 GT SWB California Spyder

Car: 1961 Ferrari 250 GT SWB California Spyder

Number produced: About 50

Price at auction: $10.9 million

One of several Ferraris to make it onto this list (the Italians are good at what they do), this was the car featured in the movie "Ferris Bueller's Day Off" -- the one that Ferris and his friend Cameron completely destroyed after taking a joyride into downtown Chicago.

To call the Spyder gorgeous is an incredible understatement. It's the classic embodiment of the sports car -- long hood, two seats and a drop top. The SWB California Spyder was a variant on the popular Ferrari 250 designed for the American market. It featured a 3.0-liter SOHC V-12 with 280 horsepower and a four-speed manual transmission [source: Motor Trend].

Actor James Coburn owned this particular Spyder for more than 20 years. At an RM Auction in 2008, British TV and radio presenter Chris Evans bought it for $10.9 million. It was a record auction sale that stood only until the next (and final) car on our list broke it the following year.

The Ferrari logo

AP Photo/Jens Meyer

1: 1957 Ferrari 250 Testa Rossa

Car: 1957 Ferrari 250 Testa Rossa

Number produced: 22

Price at auction: $12.1 million

Most people are probably more familiar with the 1980s Ferrari Testarossa, prominently featured in the TV series Miami Vice. But there was another "red head" (so named because of the red valve covers on the engine) that came first, and it was far more rare and exotic. The 1957 Ferrari 250 Testa Rossa was a GT race car that ran in many prominent contests of speed, including The 24 Hours of Le Mans.

The '57 Testa Rossa had a 3-liter, 300-horsepower, V-12 engine with an 8,000 rpm redline -- pretty impressive for a car from the 1950s -- and a stunning body. In 1958, the Testa Rossas won four of the six races to win Ferrari's third consecutive World Sports Car Championship for Constructors. Racing legend Phil Hill was behind the wheel of one of them in that championship year. Only 22 were ever built -- so it's a rare find, indeed. In Ferrari's own words: "Not only is the performance breathtaking, but the view over the bonnet when driving is simply one of the best in the world [source: Gizmag]."

This particular car, the fourth one built, has been restored several times and reunited with its original engine. When it went to auction in 2009, the Testa Rossa fetched a record-shattering $12.1 million. Who says we're in a recession?

For more information about expensive, rare and classic cars, follow the links on the next page.

George, Patrick E..  "10 Most Expensive Classic Cars"  15 June 2010.  HowStuffWorks.com. <http://auto.howstuffworks.com/10-most-expensive-classic-cars.htm>  02 June 2012.

10 Ways to Make Money on the Side

by Matt Sailor

Who wouldn't want to make a little extra cash these days?

Thinkstock/Brand X Pictures

The idea of getting rich quick and making easy money is part of the American Dream. Who hasn't spent time daydreaming about becoming one of those overnight millionaires? But your high school economics teacher was probably right: There's no such thing as a free lunch. With the exception of the occasional lottery winner, making real money takes time and effort. Still, there are legitimate ways you can make extra money to supplement the income from your day job, without breaking your back.

Click through the next 10 pages for ways you can moonlight, and end up with some money to show for it.

10: Cover Your Car with Advertisements

Have you been driving down the road and suddenly seen a car drive by plastered in ads for potato chips or an energy drink? Maybe you thought the car belonged to an employee with the company. But a number of advertising firms will actually pay drivers to have their own cars covered with ads.

Depending on the firm, the length of the promotion and your region, you can be paid between $400 and $900 per month to serve as a moving billboard. Some companies will even provide you with a car to drive, free of charge. All you have to do is sign up on the company's Web site, filling in basic demographic information [source: Autowrapped, Free Car Media]. Then, if a specific advertiser decides they want to target your particular demographic, they'll select you for a promotion. Promotions last from a few months to years, so the extra income could add up to a nice sum.

Of course, since you're chosen based on demographics and region, it could be that you sign up, never to be selected by a company, or have to wait years before being selected. If a sponsor chooses you, the amount of commitment and effort is relatively minimal. You'll be required to drive a certain number of miles per month to fulfill your contract, and you'll have to set aside four to eight hours for your car to be wrapped at the beginning of each promotion. Once the ads are removed, your car will be undamaged by the process.

9: Be an Agent for a Direct Selling Company

Before the get-rich-quick hype of eBay, there was the get-rich-quick hype of direct selling programs like Avon and Amway. But like selling on eBay, it's hard to become a millionaire selling makeup and cleaning supplies to your neighbors. According to Amway, the average salesperson earns $115 a month selling Amway products [source: Amway]. Of course, like any other kind of selling, the amount of time and energy you put in is going to affect your sales.

Direct sellers use individual salespeople to sell their products instead of using traditional retail. To join Amway, you sign up with one of the company's salespeople (or "independent business owners"). That person then provides you with catalogs and samples. As you make sales, you purchase products atwholesale from your sponsor, and keep the difference between the wholesale and the resale price as profit. You can also earn bonuses and higher sales commissions as you sell more.

Direct selling may sound like a pyramid scheme, an illegal sales operation that makes more money from the wholesale purchases of its so-called "sellers" than it does from actually selling products to customers.

But in 1979, the Federal Trade Commission decided that Amway's business model is legitimate because it doesn't require recruits to pay large up-front membership fees or make large wholesale purchases before being admitted into the program. So if you decide to become a direct seller, only sign up with programs that don't require exorbitant startup fees.

Starbucks baristas can qualify for comprehensive health, dental and vision insurance if they work at least 20 hours a week.

Starbucks

8: Work at Starbucks

OK, so it's more of a commitment than hawking old books on eBay, but Starbucks actually offers an impressive range of benefits to its employees. Most of those benefits kick in once you work an average of 20 hours per week. Employees can qualify for comprehensive health, dental and vision insurance. Starbucks also allows half-time employees (or partners) paid vacation. They can also buy stock for a discounted price and participate in the company's 401(k)program. Other competitive benefits include partial tuition reimbursements for employees attending classes and assistance grants for employees who want to adopt children. To top it all off, you can even take a free pound of coffee each week [source: Starbucks]. The company has also been consistently rated as one of the top 100 places to work by Fortune magazine [source: Fortune].

Starbucks' benefit plan is notable because it's one of the few that offers insurance to employees who work only part time. But some of those benefits are slow to take effect. Insurance benefits kick in after three months of working at least 20 hours a week, and vacation days for hourly retail workers don't kick in until after a year. So, in terms of ways to make extra money, it requires a long -term commitment to really pay off. And the base salary of $7.50 to $10 per hour may not be enough of an incentive for some people [source: Starbucks].

Freelance work like writing, graphic design and even public relations can bring in supplemental income for people with experience in those fields.

Thinkstock/Comstock

7: Work Freelance

The recession has driven more and more companies to look for contract and freelance work as an alternative to full-time positions. Farming out work to independent contractors makes sense for the bottom line because companies can pay for the work they need done, with decreased overhead expenses like benefits and setting up a physical office for each employee. In today's economy, nine in 10 companies use some amount of contract work [source: Koba]. If you have a marketable skill like graphic design, search engine optimization, Web design, public relations or writing, you can take advantage of those employers' cost cutting.

Hourly pay for freelance work tends to be higher than for salaried positions. On the other hand, you will have to account for gaps between assignments. For a company, the benefit of hiring freelancers is not having to pay them when it doesn't need them. To get started, research online markets to determine the going rate for the type of work you'll be doing. There are multiple Web sites where you can post your resume and search job listings, including elance.com, ratracerebellion.com and flexjobs.com. Some sites charge a commission to connect you with an employer, others charge a flat fee to access the listings, and some are completely free

The price of gold reached an all time high in 2010 so selling pieces you no longer wear could mean extra cash.

©iStockphoto.com/spxChrome

6: Sell Your Gold Jewelry

The global economic recession has driven gold commodity prices through the roof. The price of gold has reached an all time high as recently as Oct. 6, 2010, when it hit $1,351 per ounce [source: Wycoff]. So it's a perfect time to unload old or broken gold jewelry that you don't have any use for. But keep in mind that the ultimate price you get for the gold won't hit the $1,351 per ounce mark. That price is for pure, 24 karat gold and doesn't take into account the markup that the person buying your gold will make before reselling it. Gold below 24 karats is less pure and will bring in less.

A scrap gold buyer, the type that advertises on TV, will pay considerably less than a jeweler. If you have an attractive antique piece of jewelry, a jeweler may be a better bet. But for scrap or broken gold, you might want to use one of those scrap gold buyers. In today's market, you can get from $12 to $50 perpennyweight of scrap gold. (There are 18.229 pennyweights in an ounce). Your gold will be worth more to those buyers the more karats it has, and the more of it you have. When using a mail-in buyer, check its ratings with the Better Business Bureau to make sure is hasn't received complaints. Also, never send gold in the mail unless the envelope is insured.

5: Staff Special Events or Conventions

Trade conventions and special events are good opportunities for companies to market their products, and they usually need local people to do the work for them. That could be anything from attracting attention to a booth for a new cell phone at an electronics expo, to handing out samples of a new energy drink outside of a concert venue. Sometimes you may only have to wear a T-shirt for a company's product; other times you might be asked to dress in costume as a product's mascot. The pay is hourly. Staffing services let you post your resume, headshot and a physical description in their databases. You'll then be selected by companies running promotions on a case-by-case basis. The sponsors running the promotions use physical appearance as a key factor in picking their staff, so if the idea of getting a job based on your looks is unappealing, working with an event staffer may not be for you.

Mystery shoppers get paid to report back on their experiences doing things like shopping and dining.

Thinkstock/Photodisc

4: Become a Mystery Shopper

Mystery shoppers are people who are paid by a market research company to report on their experiences doing things like shopping, eating in restaurants and buying gas. For each assignment, the mystery shopping company will give you specific instructions on where to shop and what to look for. You'll report back on how the experience went: the customer service, the attitudes of the employees, the cleanliness of the facilities. After you submit your report, you'll be paid for your time and reimbursed for anything you bought. So on top of pocket money you can get free snacks, gas, meals or movie tickets while you work. The pay ranges from $12 to $25 per assignment [source: Secret Shopper]. The Mystery Shopping Providers Associationhas a list on its Web site of reputable mystery shopping companies. Most of them let you apply for assignments online. As with any money-making opportunity that seems too good to be true, look out for scams. Reputable mystery shopping companies will never ask you to pay money upfront to be eligible to work for them.

If you have a spare bedroom, consider renting it to earn some extra income.

Thinkstock/©iStockphoto.com

3: Rent Out a Spare Room in Your House

If you happen to have an extra room or two in your house, renting out the room can be an easy way to make money on the side. Depending on the rental market in your area, you could make anywhere from $250 to more than $1,000 per month in rent. You can check classified ads in the newspaper and sites like Craigslist to see comparable prices in your area.

But renting out a room isn't as easy as simply sitting back and collecting the money. You'll have to draw up a lease that protects your rights as a landlord, follow anti-discrimination laws when placing ads and interviewing tenants, do credit and background checks on potential tenants, keep your house compliant with state laws and local housing codes, and follow certain federal safety laws. For example, local codes might require you to purchase a new water heater or update your plumbing, and federal laws may require you to pay to have lead paint or asbestos removed. State and local laws also determine procedures for things that will come up eventually, like eviction and security deposits [source:Fannie Mae]. You will also have to pay tax on your rental income. Obviously, there can also be personal issues with sharing your house, so consider whether you're comfortable sharing your living space with someone you don't know.

2: Sell Your Eggs or Sperm

Some people may be uncomfortable with giving away their genetic material. But for those who aren't bothered by the idea of becoming the biological parent for another couple's children, donating genetic material can be profitable and even rewarding. Women who donate an egg are paid between $5,000 and $8,000 for the time and discomfort of the process. Egg donors typically must be between 20 and 30 years old, at an average weight for their height and non-smokers. The donation process is involved: daily drug injections for a month and an outpatient procedure for the donation.

Sperm donors get between $50 and $100 per donation. Donation cycles last six months to a year, with donations made up to three times a week, so the money adds up. Donors must be at least 18 years old, but can donate up until the age of 40. Most banks require that men be above average in height (5'7" or 5'9"). Some require a high school diploma, or even a college degree. Between the initial screening and regular donations, the time commitment can be great. And while the donation process is obviously simpler for sperm than eggs, men have to abstain from any sexual activity for three days before each donation.

Potential sperm and egg donors complete a family medical history questionnaire to weed out anyone with major genetic health problems. That process also involves genetic testing and physical examinations. The screening takes several weeks, and only applicants who pass are compensated. So for some, it may not be worth the time.

1: Become a Test Subject for a NASA Bed Rest Study

It sounds like an urban legend that should be right up there with Pop Rocks and Coca-Cola, but NASA will actually pay you $5,000 to lie in bed for 90 days. It may seem too good to be true, but the experiment has a scientific application. Test subjects lie with their legs elevated, and the extended lack of muscle use is similar to what astronauts experience in space. Subjects are not allowed to engage in much physical activity, but they can watch TV, read or use computers [source: Smith]. So, it might be your chance to get paid while you write a novel, learn Japanese or work on items two through 10 on this list.

But engaging in a bed rest study shouldn't be taken lightly. Individuals with serious health conditions are not eligible, and applicants have to pass a psychological screening. Sexual activity is not permitted during the study, and there can be short-term and long-term side effects. Participants lose between 1 and 2 percent of their bone mass for each month they participate in the study, and that mass may never be regained [source: Madrigal].

Sailor, Matt.  "10 Ways to Make Money on the Side"  09 November 2010.  HowStuffWorks.com. <http://money.howstuffworks.com/personal-finance/financial-planning/10-ways-make-money-on-the-side.htm>  02 June 2012.

5 NASA Inventions You Won't Believe

Space Exploration Image Gallery

Space Exploration Image Gallery The Space Shuttle Discovery lifts off from launch pad 39B on July 26, 2005, in Cape Canaveral, Fla. See more space exploration pictures.

NASA/Getty Images

by Kristen Hall-Geisler

Since its beginnings in 1958, the National Aeronautics and Space Administration (NASA) has had to invent everything it needed to make space missions possible, from protective suits for astronauts to the mirrors and software used on the Hubble telescope. But NASA was smart enough to know it couldn't do everything alone -- these are, after all, rocket scientists. It has partnered with businesses and scientists around the country to create some of the most amazing inventions the planet has ever seen, and not just Tang, the powdered orange drink famously used by astronauts on Gemini missions in the 1960s.

Take a look at these five amazing inventions, which were all developed by NASA for use in space but have found some amazing Earth-bound applications.

Ceramic-magnetic nanoparticles are good for more than fighting cancerous tumors -- they also release ions that make hair smooth and shiny.

David Woolley/The Image Bank/Getty Images

5: Nanoceramics Cure Cancer, Make Hair Shiny

While working as a NASA scientist specializing innanomaterials (which are 10,000 times smaller than a human hair), Dr. Dennis Morrison developed nanoceramics, which could be formed into tiny balloons called microcapsules. These little balloons could be filled with cancer-fighting drugs and injected into solid tumors.

Where, you're wondering, does space come into this process? In order to create the microscopic membrane around the liquid drugs, the microcapsules had to be formed in low-Earth orbit. Dr. Morrison's ceramic nanoparticles contained metals that would react when the patient was subjected to a magnetic field, like what's used in an MRI diagnostic machine. The capsules would melt, and the drugs would be released to fight the cancerous tumor.

It turns out that Dr. Morrison's ceramic-magnetic particles were good for more than fighting tumors -- they could also fight frizz. When incorporated into Farouk Systems's hairstyling iron and heated, the nanoparticles released ions that made hair smooth and shiny.

This manatee is in a river off the west coast of Florida.

Daniel J. Cox/Getty Images

4: Reflective Coatings Save Skylab, Manatees

When the Skylab space-based laboratory was set in position in 1973, a solar panel fell off during the launch, which kept another solar panel from deploying properly once in orbit. These panels had to be replaced -- and fast. NASA turned to National Metalizing, a firm it had worked with previously, to create a new panel that would be ready to go into space in 10 days.

National Metalizing had originally developed reflective materials for NASA in the 1950s, so it was able to deliver the necessary thin plastic material coated in vaporized aluminum in time. The material can deflect or conserve radiant energy, depending on which is required -- to keep something cool or to warm it up. This flexible reflective material proved so useful, it was inducted into the Space Technology Hall of Fame in 1996.

A former director of the company took this technology, which has been in the public domain for decades, and started a new company, Advanced Flexible Materials. The same materials used to protect Skylab now protects marathon runners from hypothermia after a race, as well as manatees, which can suffer from hypothermia at 60 degrees Fahrenheit (15.6 degrees Celsius), while they're being tagged by researchers.

The Hubble Space Telescope positioned over the Earth

StockTrek/Getty Images

3: Deformable Mirrors -- Not for the Fun House

Any space nerd who remembers the Hubble Space Telescope launch in 1990 remembers seeing pictures and news videos of the giant mirrors being polished to perfection -- or as close as humans can get, anyway. Minor flaws in the surface could obscure important discoveries.

Hubble and its amazing sheets of optical glass paved the way for the Terrestrial Planet Finder and its deformable mirrors, which will have 100 times the imaging power of its predecessor when NASA launches it in the near future. Deformable mirrors don't need to be absolutely perfect the first time out -- they can adjust their positions to correct for blurring or distortion, which in space can be caused by temperature, lack of gravity or getting bumped during launch.

Deformable mirrors are not so new; they were proposed by astronomers in the 1950s and developed by theUnited States Air Force in the 1970s. Each system consists of the deformable mirror itself, a sensor that measures any aberrations it finds hundreds of times a second, and a small computer that receives the sensor's readings and tells the mirror how to move to correct for the problem

Mars: The Schiaparelli Hemisphere

Digital Vision/Getty Images

2: Nanotubes Look for Life on Mars

No matter what the movies have been telling us for decades, Martians are not likely to be humanoid, sentient beings. They won't have ray guns or space suits. If there is life on Mars, it will be very, very small, and probably not too far up theevolution ladder. Pity.

In order to find such small forms of life, small detectors were necessary. Enter nanotubes, which is a fun word to say. Scientists at the Ames Research Center developed carbon nanotubes, each 1/50,000th the diameter of a human hair, that can conduct heat and electricity. Each nanotube is tipped with single strands of nucleic acid (the "NA" in "DNA") from a microorganism. When it comes into contact with a matching strand, the pair form a double helix and send a faint electrical charge through the nanotubes. This charge is how anyone looking at the biosensor, as the tiny apparatus is called, knows life has been detected.

Sadly, no life has yet been found on Mars, but these biosensors are being put to good use on Earth. Tipping the nanotubes with waterborne pathogens like E. Coli and Cryptosporidium means an analyst can get results from the biosensor in the field within two hours -- no lab work required.

The Sojourner Rover uses its Alpha Proton X-Ray Spectrometer (APXS) to analyze the Yogi Rock on the surface of Mars during the Mars Pathfinder exploratory mission in July 1997.

Space Frontiers/Hulton Archive/Getty Images

1: Mars Missions Create Tough Armor

When the Mars Pathfinder (1997) and Mars Rover (2004) missions landed on the Red Planet, they landed hard. These were unmanned missions, of course, with some guidance from engineers on Earth -- but not as much as they'd like. The equipment was designed to crash land, gently, with a cage of airbags to cushion the fall from space.

Obviously, not just any airbag would work. NASA required the material to be lightweight and able to withstand extreme temperatures for the interplanetary flight. The material also had to be tough enough to keep the airbags inflated as the whole apparatus bounced along the rocky, sharp surface ofMars.

NASA's Jet Propulsion Laboratory worked with Warwick Mills, the company that had woven the reentry parachutes for the Apollo missions in the 1960s, to create a layered, coated, liquid-crystal polyester fiber that would fit the bill.

Warwick took the technology and ran with it, creating TurtleSkin protective gear that can withstand punctures from needles, knives and even bullets. The flexibility of the tightly woven fabric, which helped keep the Mars landers safe, now also keeps military and police officers safe.

For more information about NASA inventions and other related topics, follow the links on the next page.

Hall-Geisler, Kristen.  "5 NASA Inventions You Won\u0027t Believe"  03 March 2011.  HowStuffWorks.com. <http://science.howstuffworks.com/innovation/nasa-inventions/5-surprising-nasa-inventions.htm>  02 June 2012.