First Dinosaur Fossil


“The first proof that giant dinosaurs once walked the earth.”

  • Who Discovered it?: William Buckland and Gideon Mantell.
  • Year of Discovery: 1824

How was it Discovered?

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People had always found fossil bones, but none had correctly identified them as extinct species. In 1677 English man Robert Plot found what 220 years later was identified as the end of the thigh bone of a giant biped carnivorous dinosaur. Plot gained great fame when he claimed it was the fossilized testicles of a giant and said it proved that story giants were real.

Science was clearly still in the dark ages until two English men, working independently, both wrote articles on their discovery of dinosaurs in 1824. They share the credit for discovering dinosaurs.

In 1809 (50 years before Darwin’s discovery of evolution) English country doctor Gideon Mantell lived in Lewes in the Sussex district of England. While visiting a patient one day, Mantell’s wife, Mary Ann, took a short stroll and then presented him with several puzzling teeth she had found. These massive teeth were obviously from an herbivore but were far too large for any known animal. Mantell, an amateur geologist, had been collecting fossil relics of ancient land animals for several years but could not identify these teeth. He returned to the site and correctly identified the rock strata as from the Mesozoic era. Thus, the teeth had to be many millions of years old.

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These teeth were not the first large bones Mantell had found, but they were the most puzzling. Mantell took them to famed French naturalist, Charles Cuvier, who thought they came from an ordinary rhinoceros-like animal. Mantell set the teeth aside.

In 1822 Mantell came across the teeth of an iguana and realized that these teeth were exact miniatures of the ones he had found 13 years earlier. Combined with other large bones he had recovered from the site, Mantell claimed that he had discovered an ancient, giant reptile that he named Iguanodon (“Iguana-toothed”). He eagerly published his discovery in 1824.

During this same period William Buck-land, a professor at Oxford University, had been collecting fossils in the Stonesfield region of England. During an 1822 outing, he discovered the jaw and several thigh bones of an ancient and giant creature. (It turned out to be the same species discovered—but not identified—by Robert Plot 150 years before.)

Buckland determined from these bones that this monster had been a biped (two-legged) carnivore. From the bone structure, Buckland claimed that it belonged to the reptile family. Thus he named it megalosaurus (giant lizard) and published a paper on it in 1824. With these two publications, the era of dinosaurs had been discovered.

 

Fun Facts: The word dinosaur comes from the Greek words meaning terrible lizard.” Lots of dinosaurs were named after Greek words that suited their personality or appearance. Velociraptor means “speedy robber” and Triceratops means “three-horned head.

Germs


“Microorganisms too small to be seen or felt exist everywhere in the air and cause disease and food spoilage.”

  • Who Discovered it?: Louis Pasteur
  • Year of Discovery: 1856

How was it Discovered?

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In the fall of 1856, 38-year-old Louis Pasteur was in his fourth year as Director of Scientific Affairs at the famed Ecole Normale in Paris. It was an honored administrative position. But Pasteur’s heart was in pure research chemistry and he was angry.

Many scientists believed that microorganisms had no parent organism. Instead, they spontaneously generated from the decaying molecules of organic matter to spoil milk and rot meat. Felix Pouchet, the leading spokesman for this group, and had just published a paper claiming to prove this thesis.

Pasteur thought Pouchet’s theory was rubbish. Pasteur’s earlier discovery that microscopic live organisms (bacteria called yeasts) were always present during, and seemed to cause, the fermentation of beer and wine, made Pasteur suspect that microorganisms lived in the air and simply fell by chance onto food and all living matter, rapidly multiplying only when they found a decaying substance to use as nutrient.

Two questions were at the center of the argument. First, did living microbes really float in the air? Second, was it possible for microbes to grow spontaneously (in a sterile environment where no microbes already existed)?

Pasteur heated a glass tube to sterilize both the tube and the air inside. He plugged the open end with guncotton and used a vacuum pump to draw air through the cotton filter and into this sterile glass tube.

Pasteur reasoned that any microbes floating in the air should be concentrated on the outside of the cotton filter as the air was sucked through it. Bacterial growth on the filter indicated microbes floating freely in the air. Bacterial growth in the sterile interior of the tube meant spontaneous generation.

After 24 hours the outside of his cotton wad turned dingy gray with bacterial growth while the inside of the tube remained clear. Question number 1 was answered. Yes, microscopic organisms did exist, floating, in the air. Any time they concentrated (as on a cotton wad) they began to multiply.

Now for question number 2. Pasteur had to prove that microscopic bacteria could not spontaneously generate.

Pasteur mixed a nutrient-rich bullion (a favorite food of hungry bacteria) in a large beaker with a long, curving glass neck. He heated the beaker so that the bullion boiled and the glass glowed. This killed any bacteria already in the bullion or in the air inside the beaker. Then he quickly stoppered this sterile beaker. Any growth in the beaker now had to come from spontaneous generation.

He slid the beaker into a small warming oven, used to speed the growth of bacterial cultures.

Twenty-four hours later, Pasture checked the beaker. All was crystal clear. He checked every day for eight weeks. Nothing grew at all in the beaker. Bacteria did not spontaneously generate. Pasteur broke the beaker’s neck and let normal, unsterilized air flow into the beaker. Seven hours later he saw the first faint tufts of bacterial growth. Within 24 hours, the surface of the bullion was covered.

Pouchet was wrong. Without the original airborne microbes floating into contact with a nutrient, there was no bacterial growth. They did not spontaneously generate.

Pasteur triumphantly published his discoveries. More important, his discovery gave birth to a brand new field of study, microbiology.

 

Fun Facts: The typical household sponge holds as many as 320 million disease-causing germs.

Doppler Effect


“Sound- and light-wave frequencies shift higher or lower depending on whether the source is moving toward or away from the observer.”

  • Who Discovered it?: Christian Doppler
  • Year of the Discovery: 1848

How was it Discovered?

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Austrian-born Christian Doppler was a struggling mathematics teacher—struggling both because he was too hard on his students and earned the wrath of parents and administrators and because he wanted to fully understand the geometry and mathematical concepts he taught. He drifted in and out of teaching positions through the 1820s and 1830s as he passed through his twenties and thirties. Doppler was lucky to land a math teaching slot at Vienna Polytechnic Institute in 1838.

By the late 1830s, trains capable of speeds in excess of 30 mph were dashing across the countryside. These trains made a sound phenomenon noticeable for the first time. Never before had humans traveled faster than the slow trot of a horse. Trains allowed people to notice the effect of an object’s movement on the sounds that the object produced.

Doppler intently watched trains pass and began to theorize about what caused the sound shifts he observed. By 1843 Doppler had expanded his ideas to include light waves and developed a general theory that claimed that an object’s movement either increased or decreased the frequency of sound and light it produced as measured by a stationary observer. Doppler claimed that this shift could explain the red and blue tinge to the light of distant twin stars. (The twin circling toward Earth would have its light shifted to a higher frequency—toward blue. The other, circling away, would shift lower, toward red.)

In a paper he presented to the Bohemian Scientific Society in 1844, Doppler presented his theory that the motion of objects moving toward an observer compresses sound and light waves so that they appear to shift to a higher tone and to a higher frequency color (blue). The reverse happened if the object was moving away (a shift toward red). He claimed that this explained the often observed red and blue tinge of many distant stars’ light. Actually, he was wrong. While technically correct, this shift would be too small for the instruments of his day to detect.

Doppler was challenged to prove his theory. He could n’t with light because telescopes and measuring equipment were not sophisticated enough. He decided to demonstrate his principle with sound.

In his famed 1845 experiment, he placed musicians on a railway train playing a single note on their trumpets. Other musicians, chosen for their perfect pitch, stood on the station platform and wrote down what note they heard as the train approached and then receded. What the listeners wrote down was consistently first slightly higher and then slightly lower than what the moving musicians actually played.

Doppler repeated the experiment with a second group of trumpet players on the station platform. They and the moving musicians played the same note as the train passed. Listeners could clearly hear that the notes sounded different. The moving and stationary notes seemed to interfere with each other, setting up a pulsing beat.

Having proved the existence of his effect, Doppler named it the Doppler Shift. However, he never enjoyed the fame he sought. He died in 1853 just as the scientific community was beginning to accept and to see the value of, his discovery.

The Doppler Effect is one of the most powerful and important concepts ever discovered for astronomy. This discovery allowed scientists to measure the speed and direction of stars and galaxies many millions of light years away. It unlocked mysteries of distant galaxies and stars and led to the discovery of dark matter and of the actual age and motion of the universe. Doppler’s discovery has been used in the research efforts of a dozen scientific fields.

Few single concepts have ever proved more useful. Doppler’s discovery is considered to be so fundamental to science that it is included in virtually all middle and high school basic science courses.

 

 

Fun Facts: Doppler shifts have been used to prove that the universe is expanding. A convenient analogy for the expansion of the universe is a loaf of unbaked raisin bread. The raisins are at rest relative to one another in the dough before it is placed in the oven. As the bread rises, it also expands, making the space between the raisins increase. If the raisins could see, they would observe that all the other raisins were moving away from them although they themselves seemed to be stationary within the loaf. Only the dough—their “universe”—is expanding.

The Existence of Molecules


“A molecule is a group of attached atoms. An atom uniquely identifies one of the 100+ chemical elements that make up our planet. Bonding a number of different atoms together makes a molecule, which uniquely identifies one of the many thousands of substances that can exist.”

  • Who Discovered it?: Amedeo Avogadro
  • Year of the Discovery: 1811

How was it Discovered?

2010-11-08-16-23-00-1-amadeo-avogadro-is-noted-for-his-contributions-toIf atoms are the basic building block of each element, then molecules are the basic building blocks of each substance on Earth.

Scientists were stalled by their inability to accurately imagine—let alone detect—particles as small as an atom or a molecule. Many had theorized that some tiny particle (that they called an atom) was the smallest possible particle and the basic unit of each element.

However, the substances around us were not made of individual elements. Scientists were at a loss to explain the basic nature of substances.

In the spring of 1811, 35-year-old college professor Amedeo Avogadro sat in his classroom scowling at two scientific papers laid out on his desk. Avogadro taught natural science classes at Vercelli College in the Italian mountain town of Turin. Twenty-five students sat each day and listened to Professor Avogadro lecture, discuss, and quiz them on whatever aspects of science caught his fancy. This day he read these two papers to his class, claimed that he saw an important mystery in them, and challenged his students to find it.

In the two papers, the English chemist, Dalton, and the French chemist, Gay-Lussaceach described an experiment in which they combined hydrogen and oxygen atoms to create water. Both reported that it took exactly two liters of gaseous hydrogen atoms to combine with exactly one liter of oxygen atoms to produce exactly two liters of gaseous water vapor. Dalton claimed that this experiment proved that water is the combination of two atoms of hydrogen and one atom of oxygen. Gay-Lussac also claimed it proved that a liter of any gas had to contain exactly the same number of atoms as a liter of any other gas, no matter what gas it was.

These studies were heralded as major breakthroughs for chemical study. But from his first reading, Professor Avogadro was bothered by a nagging contradiction. Both Dalton and Gay-Lussac started with exactly two liters of hydrogen and one liter of oxygen. That’s a total of three liters of gas. But they both ended with only two liters of water vapor gas. If every liter of every gas has to have exactly the same number of atoms, then how could all the atoms from three liters of gas fit into just two liters of water vapor gas?

The Turin cathedral bell chimed midnight before the answer struck Avogadro’s mind. Dalton and Gay-Lussac had used the wrong word. What if they had each substituted “a group of attached atoms” for atom?

Avogadro created the word molecule (a Greek word meaning, “to move about freely in a gas”) for this “group of attached atoms.” Then he scratched out equations on paper until he found a way to account for all of the atoms and molecules in Dalton’s and Gay-Lussac’s experiments.

If each molecule of hydrogen contained two atoms of hydrogen, and each molecule of oxygen contained two atoms of oxygen, then—if each molecule of water vapor contained two atoms of hydrogen and one atom of oxygen, as both scientists reported each liter of hydrogen and each liter of oxygen would have exactly the same number of molecules as each of the two resulting liters of water vapor (even though they contained a different number of atoms)!

And so it was that, without ever touching a test tube or chemical experiment of any kind, without even a background in chemistry, Amedeo Avogadro discovered the existence of molecules and created the basic gas law—every liter of a gas contains the same number of molecules of gas.

Avogadro’s discovery (and the related Avogadro’s Number) have become one of the cornerstones of organic and inorganic chemistry as well as the basis for the gas laws and much of the development of quantitative chemistry.

Fun Facts: The small est molecule is the hydrogen molecule—just two protons and two electrons. DNA is the largest known naturally occurring molecule, with over four billion atoms—each containing a number of protons, neutrons, and electrons.

Oceans control Global Weather


By pumping massive amounts of heat through the oceans, vast ocean currents control weather and climate on land.

  • Who Discovered it: Benjamin Franklin.
  • Year of Discovery: 1770

 

How was it Discovered?

The Atlantic Ocean’s Gulf Stream is the most important of our world’s ocean currents. It is a major heat engine, carrying massive amounts of warm water north to warm Europe. It has directed the patterns of ocean exploration and commerce and may be a major determinant of the onset of ice ages. Finally, it is the key to understanding global circulation patterns and the inter-connectedness of the world’s oceans, weather, and climates.

American statesman, inventor, and scientist Benjamin Franklin conducted the first scientific investigation of the Gulf Stream and discovered its importance to Earth’s weather and climate. His work launched a scientific study of ocean currents, ocean temperature, the interaction of ocean current with winds, and the effect of ocean currents on climate. Franklin’s discoveries mark the beginnings of modern oceanographic science.

Benjamin Franklin set out to map the Gulf Stream in order to speed transatlantic shipping. He wound up discovering that ocean currents are a major controlling factor of global climate and weather.

Ocean surface currents were noted by early Norse sailors as soon as they sailed the open Atlantic. Columbus and Ponce de Leon described the Gulf Stream current along the coast of Florida and in the strait between Florida and Cuba. Others noted North Atlantic currents over the next hundred years. However, no one charted these currents, recorded them on maps, or connected the individual sightings into a grand, ocean-wide system of massive currents.

In 1769 British officials in Boston wrote to London complaining that the British packets (small navy ships that brought passengers and mail to the colonies) took two weeks longer in their trans-Atlantic crossing than did American merchant ships. Benjamin Franklin, an American representative in London at the time, heard this report and refused to believe it. Packet ships rode higher in the water, were faster ships, and were better crewed than heavy Rhode Island merchant ships.

Franklin mentioned the report to a Rhode Island merchant captain off-loading cargo in London. This captain said it was absolutely true and happened because Rhode Island whalers had taught American merchant captains about the Gulf Stream, a 3 mph current that spread eastward from New York and New England toward England. American captains knew to curve either north or south on westward trips to avoid fighting this powerful current.

When Franklin checked, the Gulf Stream didn’t appear on any maps, nor did it appear in any of the British Navy shipping manuals. Franklin began interviewing merchant and whaling captains, recording on maps and charts their experience with the Gulf Stream current. Whalers, especially, knew the current well because whales tended to congregate along its edges.

By 1770 Franklin had prepared detailed maps and descriptions of this current. British Navy and merchant captains, however, didn’t believe him and refused to review his information. By 1773 rising tensions between England and the colonies made Franklin withhold his new findings from the British.

Franklin began taking regular water temperature readings on every Atlantic Ocean crossing. By 1783 he had made eight crossings, carefully plotting the exact course his ship took each time and marking his temperature readings on the ship’s map.

On his last voyage from France to America, Franklin talked the ship’s captain into tracking the edge of the Gulf Stream current. This slowed the voyage as the ship zigzagged back and forth using the warm water temperature inside the Gulf Stream and the colder water temperature outside it to trace the current’s boundary.

The captain also allowed Franklin to take both surface and subsurface (20 and 40 fathoms) temperature readings. Franklin was the first to consider the depth (and thus the volume) of an ocean current.

Franklin discovered that the Gulf Stream poured masses of warm water (heat) from the tropical Caribbean toward northern Europe to warm its climate. He began to study the interaction between wind and current and between ocean currents and weather. Through the brief papers he wrote describing the Gulf Stream data he had collected, Franklin brought science’s attention and interest to ocean currents and their effect on global climate.

Franklin’s description of the Gulf Stream was the most detailed available until German scientist Alexander von Humbolt published his 1814 book about the Gulf Stream based on his measurements from more than 20 crossings. These two sets of studies represent the beginnings of modern oceanographic study.

Fun Fact: The Gulf Stream is bigger than the combined flow of the Mississippi, the Nile, the Congo, the Amazon, the Volga, the Yangtze, and virtually every other major river in the world.