For example, atomic and nuclear physics studies matter on the smallest scale at which chemical elements can be identified. The physics of elementary particles is on an even smaller scale since it is concerned with the most basic units of matter; this branch of physics is also known as high-energy physics because of the extremely high energies necessary to produce many types of particles in particle accelerators. On this scale, ordinary, commonsense notions of space, time, matter, and energy are no longer valid.
Ernest Rutherford attended the free state schools throughwhen he won a scholarship to attend Nelson Collegiate School, a private secondary school. He excelled in nearly every subject, but especially in mathematics and science. Another scholarship took Rutherford in to Canterbury College in Christchurchone of the four campuses of the University of New Zealand.
It was a small school, with a faculty of eight and fewer than students. Rutherford was fortunate to have excellent professors, who ignited in him a fascination for scientific investigation tempered with the need for solid proof.
He completed this at the end ofearning a master of arts M. He was encouraged to remain yet another year in Christchurch to conduct independent research. During this period he fell in love with Mary Newton, the daughter of the woman in whose house he boarded.
They married in In Rutherford won a scholarship that had been created with profits from the famous Great Exhibition of in London. University of Cambridge In recognition of the increasing importance of science, the University of Cambridge had recently changed its rules to allow graduates of other institutions to earn a Cambridge degree after two years of study and completion of an acceptable research project.
Besides showing that an oscillatory discharge would magnetize iron, which happened already to be known, Rutherford determined that a magnetized needle lost some of its magnetization in a magnetic field produced by an alternating current.
This made the needle a detector of electromagnetic wavesa phenomenon that had only recently been discovered. In the Scottish physicist James Clerk Maxwell had predicted the existence of such wavesand between and the German physicist Heinrich Hertz had detected them in experiments in his laboratory.
He spent the next year in the Cavendish Laboratory increasing the range and sensitivity of his device, which could receive signals from half a mile away.
However, Rutherford lacked the intercontinental vision and entrepreneurial skills of the Italian inventor Guglielmo Marconiwho invented the wireless telegraph in For their ability to take silhouette photographs of the bones in a living hand, X-rays were fascinating to scientists and laypeople alike.
In particular, scientists wished to learn their properties and what they were. Thomson then studied the charge-to-mass ratio of the most common ion, which later was called the electronwhile Rutherford pursued other radiations that produced ions. Rutherford first looked at ultraviolet radiation and then at radiation emitted by uranium.
Uranium radiation was first detected in by the French physicist Henri Becquerel. Placement of uranium near thin foils revealed to Rutherford that the radiation was more complex than previously thought: He named these radiation types alpha and beta, respectively, for simplicity.
It was later determined that the alpha particle is the same as the nucleus of an ordinary helium atom—consisting of two protons and two neutrons —and the beta particle is the same as an electron or its positive version, a positron.
For the next several years these radiations were of primary interest; later the radioactive elementsor radioelements, which were emitting radiationenjoyed most of the scientific attention. Curiously, after chemical treatment, some radioelements lost their radioactivity but eventually regained it, while other materials, initially strong, gradually lost activity.
This led to the concept of half-life —in modern terms, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay—which ranges from seconds to billions of years and is unique for each radioelement and thus an excellent identifying tag.
Rutherford recognized his need for expert chemical help with the growing number of radioelements. With Soddy, Rutherford in —03 developed the transformation theory, or disintegration theory, as an explanation for radioactivity—his greatest accomplishment at McGill. Alchemy and its theories of transforming elements—such as lead to gold —had long been exorcised from so-called modern chemistry; atoms were regarded as stable bodies.
But Rutherford and Soddy now claimed that the energy of radioactivity came from within the atom, and the spontaneous emission of an alpha or beta particle signified a chemical change from one element into another.
They expected this iconoclastic theory to be controversial, but their overwhelming experimental evidence quelled opposition.
Before long it was recognized that the radioelements fell into three families, or decay series, headed by uraniumthoriumand actinium and all ending in inactive lead. Rutherford considered the alpha particle, because it had tangible mass, to be key to transformations.
He determined that it carried a positive charge, but he could not distinguish whether it was a hydrogen or helium ion. He welcomed increasing numbers of research students to his laboratory, including women at a time when few females studied science.
Medals and fellowship in the Royal Society of London came his way.Serving as the global voice for vision care products and services, The Vision Council represents the manufacturers and suppliers of the optical industry. We position our members to be successful in a competitive marketplace through education, advocacy, consumer outreach, strategic relationship building and industry forums.
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