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3.5.2 Quantization of Energy Physicist’s Profile: MAX PLANCK
Date and Location of Birth
Significant Achievements
APRIL 23, 1858 KIEL, HOLESTEIN GERMANY
Max Planck is without doubt one of the greatest physicists ever and his greatest work has to be the tenuous research that he conducted on quantum physics that opened up an altogether new branch of study in the subject.
Max Planck was awarded the Nobel Prize in Physics in 1918 for establishing a new branch of study in physics. Max Planck was awarded the Nobel Prize in Physics in 1918 for establishing a new branch of study in physics. Significant Awards He was awarded the coveted Lorentz Medal in 1927 and the Copley Medal in 1929.
Date, Age, and Location of Death
OCTOBER 4, 1947 89 GOTTINGEN GERMANY
References
https://www.thefamouspeople.com/profiles/max-planck-4977.php
Quantization of Energy: QUESTIONS Questions
1. What is a black body?
2. What is blackbody radiation?
3. What is the conflict known as the ultraviolet catastrophe?
4. How did Max Planck explain the experimental data for blackbody radiation?
5. What is a quantum? 6. What is a quantum state? 7. What is the relationship between a joule and an electron volt?
References
Your Answer A black body or blackbody is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence.
Black-body radiation is the thermal electromagnetic radiation within or surrounding a body in thermodynamic equilibrium with its environment, or emitted by a black body (an opaque and non-reflective body). It has a specific spectrum and intensity that depends only on the body's temperature, which is assumed for the sake of calculations and theory to be uniform and constant. The ultraviolet catastrophe, also called the Rayleigh–Jeans catastrophe, was the prediction of late 19th century/early 20th century classical physics that an ideal black body (also blackbody) at thermal equilibrium will emit radiation in all frequency ranges, emitting more energy as the frequency increases. At the time he proposed his radical hypothesis, Planck could not explain why energies should be quantized. Initially, his hypothesis explained only one set of experimental data—blackbody radiation. If quantization were observed for a large number of different phenomena, then quantization would become a law. In time, a theory might be developed to explain that law. As things turned out, Planck’s hypothesis was the seed from which modern physics grew. In physics, a quantum is the minimum amount of any physical entity involved in an interaction. In quantum physics, quantum state refers to the state of an isolated quantum system. A quantum state provides a probability distribution for the value of each observable, i.e. for the outcome of each possible measurement on the system. One joule is the work done to move one coulomb of electric charge through an electric field of one volt. Mathematically - 1J = 1C X 1V
C. Photoelectric Effect Physicist’s Profile: ALBERT EINSTEIN
Date and Location of Birth
March 14, 1879 Ulm, Württemberg, Germany
Significant Achievements
He provided powerful evidence that atoms and molecules actually exist, through his analysis of Brownian motion. He explained the photoelectric effect, proposing that light comes in bundles. Bundles of light (he called them quanta) with the correct amount of energy can eject electrons from metals. He proved that everyone, whatever speed we move at, measures the speed of light to be 300 million meters per second in a vacuum. This led to the strange new reality that time passes more slowly for people traveling at very high speeds compared with people moving more slowly. He discovered the hugely important and iconic equation E = mc2, which shows that energy and matter can be converted into one another. He rewrote the law of gravitation, which had been unchallenged since Isaac Newton published it in 1687. In his General Theory of Relativity, he showed that matter causes space to curve, which produces gravity. Showed that light follows the path mapped out by the gravitational curve of space. He showed that time passes more slowly when gravity becomes very strong. He became the 20th century’s most famous scientist when the strange predictions he made in his General Theory of Relativity were verified by scientific observations. He spent his later years trying to find equations to unite quantum physics with general relativity. This was an incredibly hard task, and it has still not been achieved.
Significant Awards
Albert Einstein was awarded the Nobel Prize in Physics in 1921. People are sometimes surprised to learn the award was not made for his work in special or general relativity, but for his overall services to theoretical physics and one of the works from his miracle year in 1905, specifically the discovery of the law of the photoelectric effect. The Royal Society of London awarded him its prestigious Copley Medal in 1925 for his theory of relativity and contributions to the quantum theory. The Franklin Institute awarded him the Franklin medal in 1935 for his work on relativity and the photoelectric effect. Universities around the world competed with one another to award him honorary doctorates, and the press wrote more about him than any other scientist – Einstein became a celebrity.
Date, Age, and Location of Death
April 18, 1955
https://www.biography.com/people/albert-einstein-9285408 References
Photoelectric Effect: QUESTIONS Questions
Your Answer
1. What effect did scientists originally think that the intensity of light shining on a photosensitive surface would have on electrons ejected from that surface?
When light shines on a metal, electrons can be ejected from the surface of the metal in a phenomenon known as the photoelectric effect.
2. How do observations of the photoelectric effect conflict with the predictions of classical physics?
the classical- light is a wave, light intensity determines e- ejection photoelectric- light as a photon, frequency determines e- ejection
3. How does Einstein’s theory resolve this conflict?
Albert Einstein applied the theory of quantized light to the photoelectric effect and found that the energy of the photons, or quanta of light, did depend on the light's frequency. ... Either the double-slit experiment was wrong, or else the photoelectric effect and black-body radiation were wrong.
4. What are some applications of the photoelectric effect?
5. The year 1905 is considered a “miracle year” in physics because of what four papers Albert Einstein published in this year?
References
The photoelectric effect has many practical applications which include the photocell, photoconductive devices and solar cells.
In 1905—seen by many as a "miracle year" for the theorist—Einstein had four papers published in the Annalen der Physik, one of the best known physics journals of the era. Two focused on photoelectric effect and Brownian motion. The two others, which outlined E=MC2 and the special theory of relativity, were defining for Einstein’s career and the course of the study of physics.
D. Early Models of the Atom Physicist’s Profile: JOSEPH JOHN "J. J." THOMSON
Date and Location of Birth
December 18, 1856, in Cheetham Hill, England
Discovery of the Electron – The first subatomic particle The Atom as a Plum Pudding Significant Achievements
Invention of the Mass Spectrometer Discovery that every Hydrogen Atom has only one Electron Discovery of Isotopes of Stable Elements
Thomson won the 1906 Nobel Prize in Physics recipient of the Order of Merit, was knighted in 1908 Significant Awards
Date, Age, and Location of Death
August 30, 1940 83 Cambridge, Cambridgeshire, England
https://www.thoughtco.com/j-j-thomson-biography-607780
References
Physicist’s Profile: ERNEST RUTHERFORD Date and Location of Birth
Significant Achievements
Significant Awards
August 30, 1871, in Spring Grove, New Zealand In 1895, as the first research student at the University of Cambridge’s Cavendish Laboratory in London, Rutherford identified a simpler and more commercially viable means of detecting radio waves than had been previously established by German physicist Heinrich Hertz. Also while at Cavendish Laboratory, Rutherford was invited by Professor J.J. Thomson to collaborate on a study of X-rays. German physicist Wilhelm Conrad Rontgen had discovered X-rays just months before Rutherford arrived at Cavendish, and X-rays were a hot topic among research scientists. Together, Rutherford and Thomson studied the effects of X-rays on the conductivity of gases, resulting in a paper about dividing atoms and molecules into ions. While Thomson went on to examine what would later be called an electron, Rutherford took a closer look at ion-producing radiations. Focusing on uranium, Rutherford discovered that placing it near foil resulted in one type of radiation being easily soaked up or blocked, while a different type had no trouble penetrating the same foil. He labeled the two radiation types “alpha” and “beta.” As it turns out, the alpha particle was identical to the nucleus of a helium atom. The beta particle was, in fact, the same as an electron or positron. Rutherford left Cambridge in 1902 and took up a professorship at McGill University in Montreal. At McGill in 1903, Rutherford and has colleague Frederick Soddy introduced their disintegration theory of radioactivity, which claimed radioactive energy was emitted from within an atom and that when alpha and beta particles were emitted at the same time, they caused a chemical change across elements. Rutherford and Yale Professor Bertram Borden Boltwood went on to categorize radioactive elements into what they called a “decay series.” Rutherford was also credited with discovering the radioactive gas radon while at McGill. Achieving fame for his contributions to the understanding of radioelements, Rutherford became an active public speaker, published numerous magazine articles and wrote the most highly regarded textbook of the time on radioactivity. In 1907 Rutherford returned to England, transferring to a professorship at the University of Manchester. Through further experimentation involving firing alpha particles at foil, Rutherford made the groundbreaking discovery that nearly the total mass of an atom is concentrated in a nucleus. In so doing, he gave birth to the nuclear model, a discovery that marked the inception of nuclear physics and ultimately paved the way to the invention of the atom bomb. Aptly dubbed the “Father of the Nuclear Age,” Rutherford received the Nobel Prize for Chemistry in 1908 awarded the 1908 Nobel Prize in Chemistry for his theory of atomic structure Rutherford was awarded with countless honors during his career, including several honorary degrees and fellowships from organizations such as the Institution of Electrical Engineers. In 1914 he was knighted. In 1931, he was elevated to the peerage, and granted the title Baron Rutherford of Nelson. He was also elected president of the Institute of Physics that same year.
October 19, 1937 Cambridge, England Date, Age, and Location of Death
https://www.famousscientists.org/ernest-rutherford/
References
Early Models of the Atom: QUESTIONS Questions 1. What was the Newtonian model of the atom?
2. What was the Thompson model of the atom?
3. Based on the Thomson model of the atom, what did Rutherford expect to happen when he projected positively charged alpha particles against a metal foil?
Your Answer
-----
The plum pudding model is one of several scientific models of the atom. First proposed by J. J. Thomson in 1904 soon after the discovery of the electron
Thomson's plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged "soup." Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. Based on these results, Rutherford proposed the nuclear model of the atom.
4. Why did Rutherford conclude that an atom’s positive charge and most of its mass are concentrated in the center of the atom?
Because the vast majority of the alpha particles had passed through the gold, he reasoned that most of the atom was empty space. ... He concluded that all of the positive charge and the majority of the mass of the atom must be concentrated in a very small space in the atom's interior, which he called the nucleus.
5. What was the Rutherford model of the atom?
Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus. Rutherford designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure.
6. What are two problems with Rutherford’s model of the atom?
The main problem with Rutherford's model was that he could not explain why negatively charged electrons remain in orbit, when they should instantly fall into the positively charged nucleus. This problem would be solved by Danish physicist Niels Bohr in 1913 The second flaw to his model was the fact that electrons orbit the nucleus in a circular fashion.
References
E. Bohr’s Hydrogen Atom Physicist’s Profile: NIELS BOHR
Date and Location of Birth
October 7, 1885, in Copenhagen, Denmark
Bohr's greatest contribution to modern physics was the atomic model. The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons. Significant Achievements
Significant Awards
Date, Age, and Location of Death
Liquid droplet theory Quantum theory
Bohr received the 1922 Nobel Prize in Physics for his work on atomic structures, and he would continue to come up with revolutionary theories. He worked with Werner Heisenberg and other scientists on a new quantum mechanics principle connected to Bohr's concept of complementarity, which was initially presented at an Italian conference in 1927.
November 18, 1962, Copenhagen
https://www.nobelprize.org/prizes/physics/1922/bohr/biographical/
References
Bohr’s Hydrogen Atom: QUESTIONS Questions
1. What was the Bohr model of the atom?
2. Bohr’s model of the atom follows classical physics in some respects and quantum mechanics in others. Which assumptions of the Bohr model correspond to classical physics and which correspond to quantum mechanics?
3. How does Bohr’s model of the atom account for the emission and absorption spectra of an element?
References
Your Answer The Bohr Model. in 1913 Neils Bohr suggested putting the quantum theory to the Rutherford model. Nelis Bohr's new model suggested that electrons are in fixed energy levels he called orbits. The energy of these orbits are multiples and the electrons absorb or release energy (which are protons) at certain wavelengths to move between energy levels.
Bohr’s model of the hydrogen atom started from the planetary model, but he added one assumption regarding the electrons. What if the electronic structure of the atom was quantized? Bohr suggested that perhaps the electrons could only orbit the nucleus in specific orbits or shells with a fixed radius. Only shells with a radius given by the equation below would be allowed, and the electron could not exist in between these shells.
As the photons of light are absorbed by electrons, the electrons move into higher energy levels. This is the opposite process of emission. The dark lines, absorption lines, correspond to the frequencies of the emission spectrum of the same element.
G. Dual Nature of Light Dual Nature of Light: QUESTIONS Questions
1. How does light behave at radio wavelengths and frequencies?
Your Answer Frequency is the number of cycles of a wave to pass some point in a second. The basic unit of frequency is cycles per second, or Hertz (Hzv Low-energy photons (i.e. radio) tend to behave more like waves, while higher energy photons (i.e. X-rays) behave more like particles.
2. How does light behave at visible wavelengths and frequencies?
One of the characteristics of light is that it behaves like a wave. ... Frequency and wavelength are inversely related, meaning that a low frequency wave has a long wavelength and vice versa. We can only see light within a certain range of wavelengths and frequency. This range is called the visible spectrum.
3. How does light behave at high frequencies and very short wavelengths?
Waves with higher frequency (and thus, shorter wavelengths) generally have higher energy. For a review of wavelength and wave frequency, see Wave and Wave Properties. Electromagnetic radiation occurs in packets of energy called photons.
References
H. Uncertainty Principle Physicist’s Profile: WERNER HEISENBERG
Date and Location of Birth
5th December, 1901
Werner Heisenberg ranks alongside Niels Bohr, Paul Dirac and Richard Feynmanas far as his influence on contemporary physics is concerned. He was one of the most important figures in the development of quantum mechanics, and its modern interpretation.
Significant Achievements
Heisenberg formulated the quantum theory of ferromagnetism, the neutron-proton model of the nucleus, the S-matrix theory in particle scattering, and various other significant breakthroughs in quantum field theory and high-energy particle physics are associated with him. As a prolific author, Heisenberg wrote more than 600 original research papers, philosophical essays and explanations for general audiences. His work is still available in the nine volumes of the “Gesammelte Werke” (Collected Works). Heisenberg is synonymous with the so-called uncertainty, or indeterminacy, principle of 1927, for one of the earliest breakthroughs to quantum mechanics in 1925, and for his suggestion of a unified field theory, the so-called “world formula”
Significant Awards
He won the Nobel Prize for Physics in 1932 at the young age of 31.
February 1, 1976 Date, Age, and Location of Death
74 Munich
https://www.thefamouspeople.com/profiles/werner-heisenberg-5202.php References
Uncertainty Principle: QUESTIONS Questions
1. What does Heisenberg’s uncertainty principle claim?
Your Answer Heisenberg Uncertainty Principle: The Equation. ... In a single statement, Heisenberg's Uncertainty Principle points out that both the position and momentum of a particle cannot be known at the same time. The more certain you are of one, the more uncertain you are of the other.
Mathematically we describe the uncertainty principle as the following, where `x' is position and `p' is momentum: 2. How is this principle expressed mathematically?
References
http://abyss.uoregon.edu/~js/21st_century_science/lectures/lec14.html
Date and Location of Birth
Significant Achievements
APRIL 23, 1858 KIEL, HOLESTEIN GERMANY
Max Planck is without doubt one of the greatest physicists ever and his greatest work has to be the tenuous research that he conducted on quantum physics that opened up an altogether new branch of study in the subject.
Max Planck was awarded the Nobel Prize in Physics in 1918 for establishing a new branch of study in physics. Max Planck was awarded the Nobel Prize in Physics in 1918 for establishing a new branch of study in physics. Significant Awards He was awarded the coveted Lorentz Medal in 1927 and the Copley Medal in 1929.
Date, Age, and Location of Death
OCTOBER 4, 1947 89 GOTTINGEN GERMANY
References
https://www.thefamouspeople.com/profiles/max-planck-4977.php
Quantization of Energy: QUESTIONS Questions
1. What is a black body?
2. What is blackbody radiation?
3. What is the conflict known as the ultraviolet catastrophe?
4. How did Max Planck explain the experimental data for blackbody radiation?
5. What is a quantum? 6. What is a quantum state? 7. What is the relationship between a joule and an electron volt?
References
Your Answer A black body or blackbody is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence.
Black-body radiation is the thermal electromagnetic radiation within or surrounding a body in thermodynamic equilibrium with its environment, or emitted by a black body (an opaque and non-reflective body). It has a specific spectrum and intensity that depends only on the body's temperature, which is assumed for the sake of calculations and theory to be uniform and constant. The ultraviolet catastrophe, also called the Rayleigh–Jeans catastrophe, was the prediction of late 19th century/early 20th century classical physics that an ideal black body (also blackbody) at thermal equilibrium will emit radiation in all frequency ranges, emitting more energy as the frequency increases. At the time he proposed his radical hypothesis, Planck could not explain why energies should be quantized. Initially, his hypothesis explained only one set of experimental data—blackbody radiation. If quantization were observed for a large number of different phenomena, then quantization would become a law. In time, a theory might be developed to explain that law. As things turned out, Planck’s hypothesis was the seed from which modern physics grew. In physics, a quantum is the minimum amount of any physical entity involved in an interaction. In quantum physics, quantum state refers to the state of an isolated quantum system. A quantum state provides a probability distribution for the value of each observable, i.e. for the outcome of each possible measurement on the system. One joule is the work done to move one coulomb of electric charge through an electric field of one volt. Mathematically - 1J = 1C X 1V
C. Photoelectric Effect Physicist’s Profile: ALBERT EINSTEIN
Date and Location of Birth
March 14, 1879 Ulm, Württemberg, Germany
Significant Achievements
He provided powerful evidence that atoms and molecules actually exist, through his analysis of Brownian motion. He explained the photoelectric effect, proposing that light comes in bundles. Bundles of light (he called them quanta) with the correct amount of energy can eject electrons from metals. He proved that everyone, whatever speed we move at, measures the speed of light to be 300 million meters per second in a vacuum. This led to the strange new reality that time passes more slowly for people traveling at very high speeds compared with people moving more slowly. He discovered the hugely important and iconic equation E = mc2, which shows that energy and matter can be converted into one another. He rewrote the law of gravitation, which had been unchallenged since Isaac Newton published it in 1687. In his General Theory of Relativity, he showed that matter causes space to curve, which produces gravity. Showed that light follows the path mapped out by the gravitational curve of space. He showed that time passes more slowly when gravity becomes very strong. He became the 20th century’s most famous scientist when the strange predictions he made in his General Theory of Relativity were verified by scientific observations. He spent his later years trying to find equations to unite quantum physics with general relativity. This was an incredibly hard task, and it has still not been achieved.
Significant Awards
Albert Einstein was awarded the Nobel Prize in Physics in 1921. People are sometimes surprised to learn the award was not made for his work in special or general relativity, but for his overall services to theoretical physics and one of the works from his miracle year in 1905, specifically the discovery of the law of the photoelectric effect. The Royal Society of London awarded him its prestigious Copley Medal in 1925 for his theory of relativity and contributions to the quantum theory. The Franklin Institute awarded him the Franklin medal in 1935 for his work on relativity and the photoelectric effect. Universities around the world competed with one another to award him honorary doctorates, and the press wrote more about him than any other scientist – Einstein became a celebrity.
Date, Age, and Location of Death
April 18, 1955
https://www.biography.com/people/albert-einstein-9285408 References
Photoelectric Effect: QUESTIONS Questions
Your Answer
1. What effect did scientists originally think that the intensity of light shining on a photosensitive surface would have on electrons ejected from that surface?
When light shines on a metal, electrons can be ejected from the surface of the metal in a phenomenon known as the photoelectric effect.
2. How do observations of the photoelectric effect conflict with the predictions of classical physics?
the classical- light is a wave, light intensity determines e- ejection photoelectric- light as a photon, frequency determines e- ejection
3. How does Einstein’s theory resolve this conflict?
Albert Einstein applied the theory of quantized light to the photoelectric effect and found that the energy of the photons, or quanta of light, did depend on the light's frequency. ... Either the double-slit experiment was wrong, or else the photoelectric effect and black-body radiation were wrong.
4. What are some applications of the photoelectric effect?
5. The year 1905 is considered a “miracle year” in physics because of what four papers Albert Einstein published in this year?
References
The photoelectric effect has many practical applications which include the photocell, photoconductive devices and solar cells.
In 1905—seen by many as a "miracle year" for the theorist—Einstein had four papers published in the Annalen der Physik, one of the best known physics journals of the era. Two focused on photoelectric effect and Brownian motion. The two others, which outlined E=MC2 and the special theory of relativity, were defining for Einstein’s career and the course of the study of physics.
D. Early Models of the Atom Physicist’s Profile: JOSEPH JOHN "J. J." THOMSON
Date and Location of Birth
December 18, 1856, in Cheetham Hill, England
Discovery of the Electron – The first subatomic particle The Atom as a Plum Pudding Significant Achievements
Invention of the Mass Spectrometer Discovery that every Hydrogen Atom has only one Electron Discovery of Isotopes of Stable Elements
Thomson won the 1906 Nobel Prize in Physics recipient of the Order of Merit, was knighted in 1908 Significant Awards
Date, Age, and Location of Death
August 30, 1940 83 Cambridge, Cambridgeshire, England
https://www.thoughtco.com/j-j-thomson-biography-607780
References
Physicist’s Profile: ERNEST RUTHERFORD Date and Location of Birth
Significant Achievements
Significant Awards
August 30, 1871, in Spring Grove, New Zealand In 1895, as the first research student at the University of Cambridge’s Cavendish Laboratory in London, Rutherford identified a simpler and more commercially viable means of detecting radio waves than had been previously established by German physicist Heinrich Hertz. Also while at Cavendish Laboratory, Rutherford was invited by Professor J.J. Thomson to collaborate on a study of X-rays. German physicist Wilhelm Conrad Rontgen had discovered X-rays just months before Rutherford arrived at Cavendish, and X-rays were a hot topic among research scientists. Together, Rutherford and Thomson studied the effects of X-rays on the conductivity of gases, resulting in a paper about dividing atoms and molecules into ions. While Thomson went on to examine what would later be called an electron, Rutherford took a closer look at ion-producing radiations. Focusing on uranium, Rutherford discovered that placing it near foil resulted in one type of radiation being easily soaked up or blocked, while a different type had no trouble penetrating the same foil. He labeled the two radiation types “alpha” and “beta.” As it turns out, the alpha particle was identical to the nucleus of a helium atom. The beta particle was, in fact, the same as an electron or positron. Rutherford left Cambridge in 1902 and took up a professorship at McGill University in Montreal. At McGill in 1903, Rutherford and has colleague Frederick Soddy introduced their disintegration theory of radioactivity, which claimed radioactive energy was emitted from within an atom and that when alpha and beta particles were emitted at the same time, they caused a chemical change across elements. Rutherford and Yale Professor Bertram Borden Boltwood went on to categorize radioactive elements into what they called a “decay series.” Rutherford was also credited with discovering the radioactive gas radon while at McGill. Achieving fame for his contributions to the understanding of radioelements, Rutherford became an active public speaker, published numerous magazine articles and wrote the most highly regarded textbook of the time on radioactivity. In 1907 Rutherford returned to England, transferring to a professorship at the University of Manchester. Through further experimentation involving firing alpha particles at foil, Rutherford made the groundbreaking discovery that nearly the total mass of an atom is concentrated in a nucleus. In so doing, he gave birth to the nuclear model, a discovery that marked the inception of nuclear physics and ultimately paved the way to the invention of the atom bomb. Aptly dubbed the “Father of the Nuclear Age,” Rutherford received the Nobel Prize for Chemistry in 1908 awarded the 1908 Nobel Prize in Chemistry for his theory of atomic structure Rutherford was awarded with countless honors during his career, including several honorary degrees and fellowships from organizations such as the Institution of Electrical Engineers. In 1914 he was knighted. In 1931, he was elevated to the peerage, and granted the title Baron Rutherford of Nelson. He was also elected president of the Institute of Physics that same year.
October 19, 1937 Cambridge, England Date, Age, and Location of Death
https://www.famousscientists.org/ernest-rutherford/
References
Early Models of the Atom: QUESTIONS Questions 1. What was the Newtonian model of the atom?
2. What was the Thompson model of the atom?
3. Based on the Thomson model of the atom, what did Rutherford expect to happen when he projected positively charged alpha particles against a metal foil?
Your Answer
-----
The plum pudding model is one of several scientific models of the atom. First proposed by J. J. Thomson in 1904 soon after the discovery of the electron
Thomson's plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged "soup." Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. Based on these results, Rutherford proposed the nuclear model of the atom.
4. Why did Rutherford conclude that an atom’s positive charge and most of its mass are concentrated in the center of the atom?
Because the vast majority of the alpha particles had passed through the gold, he reasoned that most of the atom was empty space. ... He concluded that all of the positive charge and the majority of the mass of the atom must be concentrated in a very small space in the atom's interior, which he called the nucleus.
5. What was the Rutherford model of the atom?
Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus. Rutherford designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure.
6. What are two problems with Rutherford’s model of the atom?
The main problem with Rutherford's model was that he could not explain why negatively charged electrons remain in orbit, when they should instantly fall into the positively charged nucleus. This problem would be solved by Danish physicist Niels Bohr in 1913 The second flaw to his model was the fact that electrons orbit the nucleus in a circular fashion.
References
E. Bohr’s Hydrogen Atom Physicist’s Profile: NIELS BOHR
Date and Location of Birth
October 7, 1885, in Copenhagen, Denmark
Bohr's greatest contribution to modern physics was the atomic model. The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons. Significant Achievements
Significant Awards
Date, Age, and Location of Death
Liquid droplet theory Quantum theory
Bohr received the 1922 Nobel Prize in Physics for his work on atomic structures, and he would continue to come up with revolutionary theories. He worked with Werner Heisenberg and other scientists on a new quantum mechanics principle connected to Bohr's concept of complementarity, which was initially presented at an Italian conference in 1927.
November 18, 1962, Copenhagen
https://www.nobelprize.org/prizes/physics/1922/bohr/biographical/
References
Bohr’s Hydrogen Atom: QUESTIONS Questions
1. What was the Bohr model of the atom?
2. Bohr’s model of the atom follows classical physics in some respects and quantum mechanics in others. Which assumptions of the Bohr model correspond to classical physics and which correspond to quantum mechanics?
3. How does Bohr’s model of the atom account for the emission and absorption spectra of an element?
References
Your Answer The Bohr Model. in 1913 Neils Bohr suggested putting the quantum theory to the Rutherford model. Nelis Bohr's new model suggested that electrons are in fixed energy levels he called orbits. The energy of these orbits are multiples and the electrons absorb or release energy (which are protons) at certain wavelengths to move between energy levels.
Bohr’s model of the hydrogen atom started from the planetary model, but he added one assumption regarding the electrons. What if the electronic structure of the atom was quantized? Bohr suggested that perhaps the electrons could only orbit the nucleus in specific orbits or shells with a fixed radius. Only shells with a radius given by the equation below would be allowed, and the electron could not exist in between these shells.
As the photons of light are absorbed by electrons, the electrons move into higher energy levels. This is the opposite process of emission. The dark lines, absorption lines, correspond to the frequencies of the emission spectrum of the same element.
G. Dual Nature of Light Dual Nature of Light: QUESTIONS Questions
1. How does light behave at radio wavelengths and frequencies?
Your Answer Frequency is the number of cycles of a wave to pass some point in a second. The basic unit of frequency is cycles per second, or Hertz (Hzv Low-energy photons (i.e. radio) tend to behave more like waves, while higher energy photons (i.e. X-rays) behave more like particles.
2. How does light behave at visible wavelengths and frequencies?
One of the characteristics of light is that it behaves like a wave. ... Frequency and wavelength are inversely related, meaning that a low frequency wave has a long wavelength and vice versa. We can only see light within a certain range of wavelengths and frequency. This range is called the visible spectrum.
3. How does light behave at high frequencies and very short wavelengths?
Waves with higher frequency (and thus, shorter wavelengths) generally have higher energy. For a review of wavelength and wave frequency, see Wave and Wave Properties. Electromagnetic radiation occurs in packets of energy called photons.
References
H. Uncertainty Principle Physicist’s Profile: WERNER HEISENBERG
Date and Location of Birth
5th December, 1901
Werner Heisenberg ranks alongside Niels Bohr, Paul Dirac and Richard Feynmanas far as his influence on contemporary physics is concerned. He was one of the most important figures in the development of quantum mechanics, and its modern interpretation.
Significant Achievements
Heisenberg formulated the quantum theory of ferromagnetism, the neutron-proton model of the nucleus, the S-matrix theory in particle scattering, and various other significant breakthroughs in quantum field theory and high-energy particle physics are associated with him. As a prolific author, Heisenberg wrote more than 600 original research papers, philosophical essays and explanations for general audiences. His work is still available in the nine volumes of the “Gesammelte Werke” (Collected Works). Heisenberg is synonymous with the so-called uncertainty, or indeterminacy, principle of 1927, for one of the earliest breakthroughs to quantum mechanics in 1925, and for his suggestion of a unified field theory, the so-called “world formula”
Significant Awards
He won the Nobel Prize for Physics in 1932 at the young age of 31.
February 1, 1976 Date, Age, and Location of Death
74 Munich
https://www.thefamouspeople.com/profiles/werner-heisenberg-5202.php References
Uncertainty Principle: QUESTIONS Questions
1. What does Heisenberg’s uncertainty principle claim?
Your Answer Heisenberg Uncertainty Principle: The Equation. ... In a single statement, Heisenberg's Uncertainty Principle points out that both the position and momentum of a particle cannot be known at the same time. The more certain you are of one, the more uncertain you are of the other.
Mathematically we describe the uncertainty principle as the following, where `x' is position and `p' is momentum: 2. How is this principle expressed mathematically?
References
http://abyss.uoregon.edu/~js/21st_century_science/lectures/lec14.html
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