Ivan Pavlov 1849-1936

1. Ivan Pavlov 1849-1936 Ivan Pavlov studied drooling dogs. While that may seem like an odd thing to research, Pavlov made some fascinating and important observations by studying when, how, and why dogs drooled when introduced to varied, controlled stimuli. During this research, Pavlov discovered "conditioned reflexes." Conditioned reflexes explain why a dog would automatically drool when hearing a bell (if usually the dog's food was accompanied by a bell being rung) or why your tummy might rumble when the lunch bell rings. Simply, our bodies can be conditioned by our sur-roundings. Pavlov's findings had far reaching effects in psychology. Note the saliva catch container and tube surgically implanted in the dog's muzzle.

2. Max Planck 1858-1947 Max Karl Ernst Ludwig Planck was a German physicist who is regarded as the founder of the quantum theory, for which he received the Nobel Prize in Physics in 1918. Planck’s constant (denoted h) is a physical constant reflecting the sizes of quanta in quantum mechanics. The Planck constant was first described as the proportionality constant between the energy (E) of a photon and the frequency of its associated electromagnetic wave (ν).

3. Max Planck didn't mean to, but he completely revolutionized physics. His work was so important that his research is considered the pivotal point where "classical physics" ended and modern physics began. It all started with what seemed an innocuous discovery -- energy, which appears to be emitted in wavelengths, is actually discharged in small packets (quanta). This new theory of energy, called quantum theory, played a role in many of the most important scientific discoveries of the 20th century.

4. Marie Curie 1867-1934 Marie Curie worked closely with her scientist husband, Pierre Curie (1859-1906), and together they discovered two new elements: polonium and radium. Unfortunately, their work together was cut short when Pierre died suddenly in 1906. (Pierre had been trampled by a horse and carriage while trying to cross a street.) After Pierre's death, Marie Curie continued to research radioactivity (a term she coined) and her work eventually earned her a second Nobel Prize. Marie Curie was the first person to be awarded two Nobel Prizes. Marie Curie's work led to the use of X-rays in medicine and laid the foundation for the new discipline of atomic physics.

5. Albert Einstein Albert Einstein (1879 –1955) was a German-born theoretical physicist who discovered the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics. He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect".Einstein published more than 300 scientific papers along with over 150 non-scientific works, and received honorary doctorate degrees in science, medicine and philosophy from many European & American universities. His great intelligence and originality has made the word "Einstein" synonymous with genius.

6. Albert Einstein may have revolutionized scientific thought, but what made the public adore him was his down-to-earth sense of humor. Known for making short quips, Einstein was the people's scientist. Despite being one of the most brilliant men of the 20th Please click on links for more info. century, Einstein appeared approachable, partly because he always had uncombed hair, disheveled clothing, and a lack of socks. During his entire life, Einstein worked diligently to understand the world around him and in so doing, developed the Theory of Relativity, which opened the door for the creation of the atomic bomb. E=mc² is the concept that the mass of a body is a measure of its energy content: Energy equals mass times speed of light squared.

7. Robert Goddard 1882-1945 Robert Goddard, considered by many to be the father of modern rocketry, was the very first to successfully launch a liquid-fueled rocket. This first rocket, named "Nell," was launched on March 16, 1926 at Auburn, Massachusetts and rose 41 feet into the air. Goddard was just 17 years old when he decided he wanted to build rockets. He was climbing a cherry tree on October 19, 1899 (a day he forever after called "Anniversary Day") when he looked up and thought how wonderful it would be to send a device to Mars. From that point on, Goddard built rockets. Unfortunately, Goddard was not appreciated in his lifetime and was even ridiculed for his belief that a rocket could one day be sent to the moon.

8. Niels Bohr Danish physicist who made fundamental contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. He was part of a team of physicists working on the Manhattan Projectat the top-secret Los Alamos laboratory in New Mexico. Bohr has been described as one of the most influential scientists of the 20th century. Niels Bohr and Albert Einstein debating quantum theory (1885-1962)

9. Niels Bohr was only 37 when he won the Nobel Prize for Physics in 1922 for his progress in understanding the structure of atoms (specifically his theory that electrons lived outside the nucleus in orbits of energy). Bohr continued his important research as the director of the Institute for Theoretical Physics at the University of Copenhagen for the rest of his life, except during World War II. During WWII, when the Nazis invaded Denmark, Bohr and his family escaped to Sweden on a fishing boat. Bohr then spent the rest of the war in England and the United States, helping the Allies create an atomic bomb. (Interestingly, Niels Bohr's son, Aage Bohr, also won the Nobel Prize for Physics in 1975.)

10. Enrico Fermi Enrico Fermi (1901 – 1954) was an Italian physicist particularly known for his work on the development of the first nuclear reactor, Chicago Pile-1, and for experimentingwith neutrons, which led to the splitting of the atom. Fermi is also responsible for discovering how to create a nuclear chain reaction, which led directly the creation of the atomic bomb. He was awarded the 1938 Nobel Prize in Physics for his work on induced radioactivity. Along with J. Robert Oppenheimer, he is frequently referred to as "the father of the atomic bomb". He also held several patents related to the use of nuclear power.

11. Werner Heisenberg Werner Heisenberg (1901 – 1976) was a German theoretical physicist who made foundational contributions to quantum mechanics and is best known for asserting the uncertainty principle of quantum theory. Heisenberg was awarded the 1932 Nobel Prize in Physics for the creation of quantum mechanics, and its application especially to the discovery of the allotropic forms of hydrogen. Heisenberg DID NOT work on the Manhattan Project, but he had been friends with Bohr.

12. Linus Pauling 1901-1994 Linus Pauling was an American chemist, biochemist, peace activist, author and educator. He was one of the most influential chemists in history and ranks among the most important scientists of the 20th century. Pauling was among the first scientists to work in the fields of quantum chemistry and molecular biology. In later years, Pauling championed large doses of vitamin C to combat colds and promote long life, but this theory remains controversial.

13. Pauling is one of only four individuals to have won more than one Nobel Prize. He is one of only two people awarded Nobel Prizes in different fields (the Chemistry and Peace prizes), the other being Marie Curie (the Chemistry and Physics prizes), and the only person awarded two unshared prizes. The Nobel Prize Committee awarded Pauling the Nobel Peace Prize, describing him as "Linus Carl Pauling, who ever since 1946 has campaigned ceaselessly, not only against nuclear weapons tests, not only against the spread of these armaments, not only against their very use, but against all warfare as a means of solving international conflicts." Click here for interesting article on Pauling

14. J. Robert Oppenheimer Julius Robert Oppenheimer (1904 - 1967) was an American theoretical physicist and professor of physics at the University of California. He is best known for his role as the scientific director of the Manhattan Project, the World War II project that developed the first nuclear weapons, for which he is often referred to as the "father of the atomic bomb".In reference to the Trinity test in New Mexico, where the first atomic bomb was detonated, Oppenheimer famously recalled the BhagavadGita: "If the radiance of a thousand suns were to burst at once into the sky, that would be like the splendor of the mighty one... Now, I am become Death, the destroyer of worlds."

15. Seaborg was an American scientist who won the 1951 Nobel Prize in Chemistry for “discoveries in the chemistry of the transuranium elements.” Seaborg was the principal or co-discoverer of ten elements: plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium and element 106, which was named seaborgium in his honor while he was still living. Seaborg's theoretical development of the actinide concept resulted in a redrawing of the Periodic Table of the Elements into its current configuration with the actinide series appearing below the lanthanide series. Glenn T. Seaborg 1912-1999

16. In 1942, Seaborg joined the Manhattan Project where Enrico Fermi and his group would later convert U238 to plutonium in the world's first controlled nuclear chain reaction. Seaborg's role was to figure out how to extract the tiny bit of plutonium from the mass of uranium. He was responsible for the multi-stage chemical process that separated, concentrated and isolated plutonium. President Kennedy and his Atomic Energy Commission Chairman, Glenn Seaborg. Seaborg advised ten presidents from Harry S. Truman to Bill Clinton on nuclear policy and was the chairman of the United States Atomic Energy Commission from 1961 to 1971 where he pushed for commercial nuclear energy and peaceful applications of nuclear science.

17. Jonas Salk 1914-1995 Jonas Salk became a hero overnight when it was announced that he had invented a vaccine for polio. Before Salk created the vaccine, polio was a devastating viral disease that had become epidemic. Each year, thousands of children and adults either died from the disease or were left paralyzed. (U.S. President Franklin D. Roosevelt is one of the most famous polio victims.) By the early 1950s, polio epidemics had been increasing in severity and polio had become one of the most feared childhood diseases. When the positive results from an extensive test trial of the new vaccine was announced on April 12, 1955, exactly ten years after Roosevelt's death, people celebrated around the world. Jonas Salk became a beloved scientist.

18. Albert Sabin 1906-1993 Sabin was a Polish-born U.S. physician and microbiologist. He grew poliovirus in human nerve tissue outside the body, showed that it does not enter the body through the respiratory system, and proved that poliomyelitis is primarily an infection of the digestive tract. He postulated that an oral vaccine would work longer than Jonas Salk's injections of killed virus, and he isolated weakened strains of each of the three types of poliovirus that would stimulate antibody production but not produce disease. The Sabin oral polio vaccine, approved for use in the U.S. in 1960, became the main defense against polio throughout the world.

19. James Watson 1928- Francis Crick 1916-2004 Francis Crick and James Watson together discovered the double helix structure of DNA, the "blueprint of life." Surprisingly, when news of their discovery was first published, in Nature on April 25, 1953, Watson was just 25 years old and Crick, although older than Watson by little more than a decade, was still a doctoral student. After their discovery was made public and the two men became famous, they went their separate ways, rarely speaking to each other. This may have been in part because of personality conflicts. Although many considered Crick to be talkative and brash, Watson made the very first line of his famous book, The Double Helix (1968): "I have never seen Francis Crick in a modest mood." Ouch!

20. Stephen Hawking Stephen William Hawking (born 8 January 1942) is an English theoretical physicist and cosmologist, whose scientific books and public appearances have made him an academic celebrity. He is an Honorary Fellow of the Royal Society of Arts and a lifetime member of the Pontifical Academy of Sciences. He is known for his contributions to the fields of cosmology and quantum gravity, especially in the context of black holes. He has also achieved success with works of popular science in which he discusses his own theories and cosmology in general; these include the runaway best sellerA Brief History of Time, which stayed on the British Sunday Times bestsellers list for a record-breaking 237 weeks.

21. U.S. President Barack Obama talks with Stephen Hawking in the Blue Room of the White House before a ceremony presenting him and fifteen others the Presidential Medal of Freedom in 2009. The Medal of Freedom is the nation's highest civilian honor. Hawking's key scientific works to date have included providing, with Roger Penrose, theorems regarding gravitational singularities in the framework of general relativity, and the theoretical prediction that black holes should emit radiation, which is today known as Hawking radiation (or sometimes as Bekenstein–Hawking radiation). Hawking has a motor neurone disease that is related to amyotrophic lateral sclerosis, a condition that has progressed over the years and has left him almost completely paralysed.