lunes, 3 de enero de 2011

Neatorama com * Scientists

Neatorama com

Every high school physics student knows about Fourier’s Law of Heat Conduction and Hooke’s Law of Elasticity.
.
But not many know that Joseph Fourier lived inside a wooden box in his old age.
.
Or that Robert Hooke’s arch-nemesis, Isaac Newton, hated him so much that he had Hooke’s portrait removed from the Royal Society and tried to have his papers burned. Imagine how much fun science class would’ve been, had these been taught along side all those equations and formulas.
.
Well, now you can read about the interesting stuff that your school textbooks didn‘t bother to include. In his latest book, Archimedes to Hawking: Laws of Science and the Great Minds Behind Them, Cliff Pickover takes some 40 eponymous laws of physics and explains the life of the scientists whom these laws are named after. The book is far from a dry listing of scientific formulas - actually, it’s full of quirky trivia and nifty facts about some of the world’s greatest scientists.
.
Cliff has graciously allowed us to take samples from the book for this article and generously offer personalized copies of the book to 3 lucky Neatorama readers (see below for details).
.
So, if you didn’t know that Archimedes sometimes sent his colleagues false theorems in order to trap them when they stole his ideas, or that Daniel Bernoulli‘s father threw him out for winning a science competition, then this Neatorama post is for you. Behold, the 5 Scientific Laws and the Scientists Behind Them (no complicated math, we promise!)
.
1. Archimedes’ Principle of Buoyancy
The Law: According to Archimedes’ principle, a body wholly or partially submerged in liquid is buoyed up by a force equal to the weight of the displaced liquid. This buoyant force depends on the density of the liquid and the volume of the object, but not its shape.
.
The law seems simple, but it is actually not intuitive that objects with equal volume experience the same buoyant force when held under water: cubes made of cork and lead would experience the same buoyant force, yet would have completely different behavior. This is because the different ratios of buoyant force to object weights.
.
Archimedes’ Principle of Buoyancy has many applications, including determining the pressure of a liquid as a function of depth. It helps us understand how floatation works and is one of the founding principles of hydrostatics.
.
The Famous Legend Behind the Law: One day, King Hieron II of Syracuse, Sicily, wanted to find out whether his wreath-shaped crown was actually made from pure gold. He called upon Archimedes to find out (without damaging the crown, say by melting it down). Roman architect and engineer Marcus Vitruvius wrote:
.
While Archimedes was turning the problem over, he chanced to come to the place of bathing, and there, as he was sitting down in the tub, he noticed that the amount of water which flowed over the tub was equal to the amount by which his body was immersed. This showed him means of solving the problem … In his joy, he leapt out of the tub and, rushing naked toward his home, he cried out with a loud voice that he had found what he sought.
.
Archimedes was able to obtain the exact volume of the crown by dunking it in water and measuring the displaced water. He then took the weight of the crown and divided it by its volume to get the density of the crown, which turned out to be between that of gold and silver. Archimedes was thus able to show that the wreath was not made out of pure gold (and the royal goldsmith was executed).
.
Modern scholars suggest that this story was bogus, as it would be unlikely that Archimedes had measuring equipment with sufficient accuracy to detect the difference (plus, he hated to bathe - see below).
.
The Man Behind the Law: Archimedes of Syracuse (287-212 B.C.), was a Greek geometer and is often regarded as one of the greatest mathematicians and scientists who ever lived. Here are a few things about Archimedes you may not know:
.
- Plutarch wrote that Archimedes was so obsessed with math that his servants had to force him to bathe, and that while they scrubbed him, he continued to draw geometrical figures on his body!
.
- Archimedes invented a machine called the Archimedean screw to pump water.
.
- He also invented a “death ray” weapon using a set of mirrors that focused sunlight on Roman ships, setting them on fire. After many scientists discounted the story as false, David Wallace of MIT actually did the experiment: He had his students build an oak replica of a Roman ship and focused sunlight on it using 127 mirrored tiles from a distance of 30 meters. After ten minutes of exposure, the ship burst into flames!
.
- When the Romans captured Syracuse in 212 B.C., a Roman soldier came upon the mathematician who was studying a mathematical diagram drawn in the sand. Archimedes was annoyed by the soldier’s interruption, and said “Don’t disturb my circles” before he was killed. Moral of the story: don’t piss off a Roman soldier!
.
2. Hooke’s Law of Elasticity
The Law: Hooke’s Law of Elasticity states that if an object, such a spring, is elongated by some distance x, then the restoring force F exerted by the object is proportional to x:
The k is a constant called the spring constant if the object is a spring.
.
The Man Behind the Law: Robert Hooke (1635 - 1702) was an English physicist and polymath. As you can see, Hooke was an ugly man (he was severely disfigured by smallpox). (Photo: Molecular Expressions: Science, Optics and You)
.
Here are a few things about Hooke you may not know:
- Robert Hooke was a sickly child and wasn’t expected to reach adulthood, so his parents didn’t bother educating him. Left to his own devices, Hooke made mechanical models and clocks.
.
- He was the first to coin the word “cell” to describe the basic unit of life (he thought that plant cells, when magnified through a microscope, looked like “cellula,” the living quarters of monks).
- Hooke was a busy man: he was the Surveyor to the City of London, helped rebuild the city after the Great Fire in 1666, and even designed the infamous Bethlem Royal Hospital (“Bedlam”) and the Royal College of Physicians.
- In 1672, Hooke criticized Isaac Newton who used a prism to split white light into its various components. Furious at Hooke, Newton had his portraits removed from the Royal Society and even attempted to burn his papers. Hooke mentioned to Newton about a possible inverse-square principle of gravitation, but Newton didn’t credit Hooke when he published Principia Mathematica, saying "Merely because one says something might be so, it does not follow that it has been proved that it is."
- Hooke was interested in the science of respiration, so he had himself placed in a sealed vessel from which air was gradually pumped out. As you can imagine, the experiment was detrimental to Hooke’s health: he damaged his ears and experienced deafness in the process.
- In 2006, the Royal Society purchased a manuscript by Hooke for \$1.75 million, in which he wrote 500 pages of notes recorded during Royal Society meetings. In the notes, Hooke castigated Newton and Robert Boyle for stealing his ideas. He also wrote that Dutch microscopist Anton van Leeuwenhoek found "a vast number of small animals in his Excrements which were most abounding when he was troubled with a Looseness and very few or none when he was well."
3. Bernoulli's Law of Fluid Dynamics (Bernoulli's Principle)
The Law: Imagine fluid flowing steadily through a pipe that carries it from the top to the bottom of a hillside. The pressure of the liquid changes along the pipe, and Daniel Bernoulli discovered the law that relates the pressure, flow speed, and height for a fluid flowing in a pipe. Today, this law is written as:
You may not be aware of Bernoulli's Law, but it has numerous applications in real life: Bernoulli's Law is used when designing the Venturi throat, a constricted region in the air passage of a car motor's carburetor that causes a reduction in pressure, and in turn causes fuel vapor to be drawn out of the carburetor bowl.
The design of airplane wings take advantage of the knowledge we gleaned from Bernoulli's Law: these wings are designed to create an area of fast flowing air on its upper surface, which cause pressure near this area to drop and thus pull the wing upward.
Finally, we've all experienced Bernoulli's Law in action: the shower curtain is pulled inward when water first comes out of the shower because the increase in water and air velocity inside the shower causes pressure to drop. The pressure difference between the outside and inside of the curtain causes it to be sucked inward.
The Man Behind the Law: Daniel Bernoulli (1700-1782) was polymath that came from a family of extraordinary Swiss mathematicians. In fact, his father, Johann Bernoulli, and his uncle, Jacob, were famous mathematicians.
Interestingly, both Daniel and his father Johann secretly studied mathematics against the wishes of their respective fathers. Just as Johann's father tried to force him into becoming a merchant, Johann did the same to Daniel. Indeed, Johann had his son's future all mapped out, including whom to marry!
Finally, Daniel told his father that he'd had enough, and both of them came to a truce: Daniel would become a doctor and Johann would personally teach him math.
Here are a few things about Daniel Bernoulli you may not know:
- Johann had always been jealous of Daniel's success. In 1735, after both the father and son tied for first place in a science competition held by the Paris Academy of Sciences, Johann was unable to bear the “shame" of being comparable to his son and threw Daniel out of his house for winning the prize that he felt should've been his alone!
- Daniel published his work on fluid physics in a book titled Hydrodynamica (where we get the word "hydrodynamics" from) in 1734. Johann became jealous of Daniel's work and published his own plagiarized version, Hydraulica … and predated it to 1732 to make it seem that his work appeared before his son's!
- Daniel was a prolific author and wrote on whatever subjects struck his fancy. One of his papers discussed the formula for computing the relationship between the number of oarsmen on a ship and the ship's velocity. In another paper, Daniel wrote what would become the basis of the economic theory of risk aversion and overall happiness gained from goods or services.
4. Dalton's Law of Partial Pressures
The Law: Dalton's Law of Partial Pressures states that the total pressure Pt exerted by a mixture of gases in a container is equal to the sum of the separate pressures that each gases would exert if just that single gas occupied the entire volume of the container.
That may seem trivial, but it's actually one of the more useful gas laws for scientists.
The Man Behind the Law: John Dalton (1766 - 1844) grew in a poor family, was a poor speaker, severely color-blind, and was even considered a crude or simple experimentalist. Yet, he achieved significant professional successes and made great contributions to chemistry, meteorology, and physics.
In the early 19th century, Dalton developed the atomic theory, in which he proposed that each chemical element is composed of atoms of single, unique type and that though these atoms are indestructible, they can combine in simple ratios. For this, many consider Dalton to be the "Father of Chemistry".
Here are a few things about John Dalton you may not know:
- Legend has it that Dalton once bought his mother special stockings for her birthday. The mother, a Quaker woman, was shocked that he would buy her scarlet stockings. Dalton thought that they were blue, and asked his brother … who also saw them as blue! At that point, he realized that both he and his brother were color blind.
- Dalton did the first systematic study of color blindness and wrote the very first paper on the subject. In his honor, color blindness is sometimes called Daltonism.
- Since he was 21, Dalton kept a detailed diary of the weather, and continued to update it until the very day of his death. Dalton was so obsessed with records that he kept meticulous records of hits, misses, and other scores when he played the English game of lawn bowling!
- Dalton never married, saying "My head is too full of triangles, chymical process, and electrical experiments, etc., to think much of marriage."
- After his death, and according to his wishes, one of Dalton's eyes was cut open to determine the cause of his color blindness (Dalton had always thought that it was due to colored fluid inside his eyes - but that turned out not to be the case.) In the 1990s, cellular analysis revealed that the eye lacked the pigment that provides sensitivity to green.
5. Fourier's Law of Heat Conduction
The Law: Fourier's Law of Heat Conduction deals with the transmission of heat in materials. The law states that the heat flux, Q (the flow of heat per unit area and per unit of time), is proportional to the gradient of the temperature difference.
Fourier's Law is used in many diverse areas of science, and it explains why diamonds are cool to the touch (they have high thermal conductivity).
The Man Behind the Law: Jean Baptiste Joseph Fourier (1768 - 1830) was a French mathematicians and Egyptologist.
Here are a few things about Fourier you may not know:
- When he was only 16, Fourier discovered a new proof of Descartes’ rule of signs. His teenage achievement quickly became standard proof. By the age of 21, however, Fourier was in doubt whether he could ever make a significant contribution to mathematics. He wrote to his professor "Yesterday was my 21st birthday, at that age Newton and Pascal had already acquired many claims to immortality." It’s a good thing Fourier carried on!
- Instead of a career in science, young Fourier seriously considered being a priest. Indeed, he arrived at the Benedictine abbey of St. Benoit-sur-Leoire to prepare for his vows, but left when he realized that he only had one true love: mathematics.
- During the French Revolution, Fourier tried to defend scientists like Antoine Lavoisier, the founder of modern chemistry. Appeals to spare Lavoisier’s life was cut short when the judge said “The Republic has no need for geniuses” and he was guillotined. Afterwards, Fourier was thrown in prison but managed to escape death when the political climate changed.
- In his work on heat propagation in thin sheets of material, Fourier invented a very useful mathematical tool that would later become known as the Fourier Series. Here, Fourier showed that any periodic function can be represented by a sum of simple sine and cosine oscillating functions.
- Fourier accompanied Napoleon to Egypt. When he returned, Fourier had a strange medical condition: he was always cold and had to wear several overcoats, even in the heat of summer. It’s ironic to think that though he was an expert in heat transfer, Fourier was not good at regulating his own body heat!
- Global warming? Blame Fourier - he came up with the idea that the atmosphere acts as a “translucent dome,” which like a lid of a pot, absorbs some of the heat of the Sun and reradiates it downward to Earth.
- During his last months, Fourier’s body was so frail that he would live inside a wooden box with holes cut out for his head and arms. This “living coffin” would keep his body upright and let him work on his correspondence!

The article above is but a small selection of the amazing trivia and fascinating stories about some of the greatest names in science. If you love science, or would like to instill the love of science to your children, pick up Cliff Pickover's Archimedes to Hawking: Laws of Science and the Great Minds Behind Them. You won't be disappointed
.
Links: Archimedes to Hawking Amazon page The book's website Cliff's website
On a personal note, this article took way longer than I thought (and I didn't even get to Stephen Hawking!) ... because I ended up reading Cliff's book from cover to cover! It was definitely an interesting read.
.
Now, like I mentioned above, Cliff has generously offered free copies of Archimedes to Hawking to Neatorama readers with the most interesting experience with science or funny personal story about a science class ... Write yours in the comment section; the best three will win a free personalized copy of Cliff's book (so make it good!)
-
http://www.neatorama.com/2008/05/12/5-scientific-laws-and-the-scientists-behind-them/