In 1945, Hodgkin was considered the world's foremost practitioner of X-ray diffraction techniques, so it's not surprising that she eventually revealed the structure of one of medicine's most important chemicals -- penicillin. Imagine you drop a bowling ball from one hand and a feather from the other. Born in 1867 in Warsaw, she immigrated to Paris at age 24 for the chance to further study math and physics. Clearly, the mica was scattering some alpha particles, but how and why? They estimated its value to within whiskers of the currently accepted charge of one electron (1.602 x 10-19 coulombs). The two knew this, but they didn't know which component -- protein or DNA -- was responsible until their ingenious "blender" experiment directed them to DNA's nucleic acids. Becquerel had discovered these rays accidentally when he left uranium salts in a dark room and returned to find that they had exposed a photographic plate. Milgram wanted to know how far ordinary people would go in delivering painful shocks to a peer, when commanded to do so by a … From this observation, Marie deduced that the emission of radiation had nothing to do with a substance’s molecular arrangements. ­Until the stunning global eradication of smallpox in the late 20th century, smallpox posed a serious health problem. The authority figure began each experiment by showing the unknowing volunteer how to use the mock shock machine. But Pavlov’s dogs had learned to associate the appearance of an experimenter with meals, meaning the canines’ experience had conditioned their physical responses. By 1908, Millikan found himself pushing 40 without a significant discovery to his name. He published the full theory in a 1628 book, De Motu Cordis [The Motion of the Heart]. Get unlimited access when you subscribe. “He had been crossing different varieties, trying to get new colors or combinations of colors, and he got repeatable results that suggested some law of heredity at work.”, These laws became clear with his cultivation of pea plants. Which will fall faster? How Rainbows f... How Storm Chasers Work? Adding or removing the rods could control the longevity of the chain reaction. Born in 1822 in what is now the Czech Republic, Mendel showed a knack for the physical sciences, though his farming family had little money for formal education. ­Today, scientists know that cowpox viruses and smallpox viruses are so similar that the body's immune system can't distinguish them. Lubchenco, the administrator of the National Oceanic Atmospheric Administration from 2009 to 2013, saw over the years the impact that Paine’s keystone species concept had on policies related to fisheries management. Adam Hadhazy is based in New Jersey. Clouds of water droplets formed around charged atoms and molecules before descending due to gravity. Tiny crystals ready for structural analysis by X-ray crystallography, George Karger/Pix Inc./Time Life Pictures/Getty Images, Harold Urey, one of the two biochemists who helped to figure out how life got started. In 1878, physics instructor A.A. Michelson devised an experiment to calculate the speed of light and prove that it was a finite, measurable quantity. Louis Pasteur didn’t – he rejected the idea that mice could be randomly created from rotting wheat and old cloth over a few weeks. Overturning all this dogma took a series of often gruesome experiments. Subsequent double slit-style experiments with electrons proved that particles with matter and undulating energy (light) can each act like both particles and waves. If the light beams arrive at different times, due to some sort of unequal displacement during their journeys (say, from the ether wind), they create a distinctive interference pattern. With so many scientists conducting so many experiments every year both in and out of the lab, it's not surprising that most investigations enjoy little acclaim. Pavlov published his results in 1903. ­Rutherford concluded that a strong positive charge at the heart of the gold atoms was deflecting the alpha particles straight back toward the source. How Storm Chasers Function... What is Weather? For her doctoral thesis in 1897, Marie began investigating a newfangled kind of radiation, similar to X-rays and discovered just a year earlier. To test the accuracy of this ‘plum pudding’ model — under the direction of Ernest Rutherford — Hans Geiger and Ernest Marsden performed a series of experiments between 1908–1913 to prove Rutherford’s theory of an atomic model, which resembled planets orbiting the Sun. In order for Einstein’s theory to be correct, Eddington had to prove that the light had been bent by a source of intense gravity, such as the Sun. Simply put, an electrical generator is a device that converts mechanical … Win one of three smart trackers worth £49! Whether elegant or crude, and often with a touch of serendipity, these singular efforts have delivered insights that changed our view of ourselves or the universe. Young reasoned that this pattern emerged from light wavily spreading outward, like ripples across a pond, with crests and troughs from different light waves amplifying and canceling each other. While his scientific legacy will always be tied to doggie drool, it is the operations of the mind — canine, human and otherwise — for which Pavlov remains celebrated today. Can animals predict the weather? Gauging gastric secretions was no picnic. Neither researcher fully grasped the significance of their null result. In this harsh environment, they suggested, organic compounds could form from simple molecules if they were stimulated by a strong source of energy, either ultraviolet radiation or lightning.