- Ancient Greek thinkers like Aristotle and Plato made early observations about light reflection but did not understand the nature of light.
- In the 17th century, Isaac Newton proposed his particle theory of light to explain properties like reflection and refraction, while Christian Huygens proposed a wave theory.
- Newton's particle theory was more widely accepted at the time because it better explained observations like light traveling in straight lines and through a vacuum, and the existence of different colors, though it could not fully account for refraction.
This theory, not so much to unify the gravitational field, but gives us a theoretical concept of the universe can be correlated, hence derives DEPENDABILITY universal, by the fact that unifies all the theories that exist, notably Einstein's general relativity and the theory of dynamic gravity of tesla, and among others.
This theory, not so much to unify the gravitational field, but gives us a theoretical concept of the universe can be correlated, hence derives DEPENDABILITY universal, by the fact that unifies all the theories that exist, notably Einstein's general relativity and the theory of dynamic gravity of tesla, and among others.
Gifford Lecture One: Cosmos, Time, MemorySean Carroll
Based on my book The Big Picture, this is the first of five lectures exploring how different ways of talking about the world fit together. The other four lectures are on YouTube.
Red shift and Blue shift – By Virtue of B-Bit (YIN - Mass reality ) Property ...iosrjce
To understand red shift and blue shift and other properties of photons , we have to understand Basic
Building Blocks of the universe as shown in Fig 1. ( mass – B.B.B Bit or B-Bit ) and Divine Mechanics Unit (
CCP , Code PcPs and CP ). Red shift and blue shift is acquired and conditioned property of mass part of
basic Building blocks and it is ( type of red shift and blue shift ) by virtue of Atomic genes part of reality . Hence
it is affected by outer stimuli like direction and magnitude of velocity. Photon motion is due to inherent
property of motion in all direction and in all type of property of mass of Yin part of Basic building blocks . The
mass property of Yin B.B.B is not a dead part reality of God particles rather it could connect itself with mind
part of reality to follow all orders made by CCP . Once the information’s ( Code PcPs- spin , velocity ,
directions , magnitude , type of red shift and blue shift etc ) are formed , the mass of Yin translates it and it
works accordingly .
Question on the nature of the particle wave. de Broglie and other scientists struggled to find out but failed. Ended in the probability interpretation.
September 2015, the LIGO detectors in the USA saw space vibrate with gravitational waves for the very first time. Although the signal was extremely weak when it reached Earth, it is already promising a revolution in astrophysics.
The theory of light that was stated by Imam Jaffar Sadiq(as) 1400 years ago. Imam Sadiq (as) was the grandson of Prophet Muhammad (as) and is the 6th holy Imam of the Muslims as followd by Shia Muslims
LECTURE 13. LIGHTHubble space telescope observations have tak.docxwashingtonrosy
LECTURE 13. LIGHT
Hubble space telescope observations have taken advantage of gravitational lensing to reveal the largest sample of the faintest and earliest known galaxies in the universe. Some of these galaxies formed just 600 million years after the Big Bang.
Space, mass, light and time are fundamental descriptors of our Universe. Captured by the poetry in Genesis, “In the beginning, when God created the heavens and earth, the earth was a formless wasteland, and darkness covered the abyss, while a mighty wind swept over the waters. Then God said “Let there be light,” and there was light.
The cosmological model of the “Big Bang” describes how the universe expanded from an initial state of very high density and high temperature. If observed conditions today areextrapolated backwards in time using the known laws of physics, the prediction is that our Universe emerged from a singularity, a point of infinite density, and that before this event, space and time did not exist.
Current knowledge is insufficient to determine if anything existed prior to the singularity. Sixteen centuries ago, in his Confessions, Saint Augustine (354-430) posed the obvious question in biblical terms: What was God doing before he created the Universe?
ISAAC NEWTON: COLOR SPECTRUM and the CORPUSCULAR THEORY of LIGHT
Our modern understanding of light and color begins with Isaac Newton (1642-1726) and a series of experiments that he published in 1672. He was the first to understand the rainbow. He refracted white light with a glass prism, resolving it into its component colors: red, orange, yellow, green, blue and violet.
In the graphic below, light enters the prism from the top right, and is refracted by the glass. The violet is bent more than the yellow and red, so the colors separate.
In the 1660s, Newton began experimenting with his “celebrated phenomenon of colors.” At the time, people thought that color was a mixture of light and darkness, and that prisms colored light. Hooke was a proponent of this theory of color, and had a scale that went from brilliant red, which was pure white light with the least amount of darkness added, to dull blue, the last step before black, which was the complete extinction of light by darkness. Newton believed this theory was false.
Newton set up a prism near a window at his boyhood home in Woolsthorpe, England ( site of the famous apple tree), and projected a beautiful spectrum 22 feet onto the far wall. Further, to prove that the prism was not coloring the light, he refracted the spectral light back together, producing white light. Incidentally, he was at home because all the students at Cambridge University where he was a student were sent home because of an epidemic of the bubonic plague. In 1665, it was a version of “social distancing.” BTW, Newton did his best work working from home.
On a personal note, my wife and I once visited the hometown of William Shakespeare (1564-1616), Stratford-upon-Avon..
Gifford Lecture One: Cosmos, Time, MemorySean Carroll
Based on my book The Big Picture, this is the first of five lectures exploring how different ways of talking about the world fit together. The other four lectures are on YouTube.
Red shift and Blue shift – By Virtue of B-Bit (YIN - Mass reality ) Property ...iosrjce
To understand red shift and blue shift and other properties of photons , we have to understand Basic
Building Blocks of the universe as shown in Fig 1. ( mass – B.B.B Bit or B-Bit ) and Divine Mechanics Unit (
CCP , Code PcPs and CP ). Red shift and blue shift is acquired and conditioned property of mass part of
basic Building blocks and it is ( type of red shift and blue shift ) by virtue of Atomic genes part of reality . Hence
it is affected by outer stimuli like direction and magnitude of velocity. Photon motion is due to inherent
property of motion in all direction and in all type of property of mass of Yin part of Basic building blocks . The
mass property of Yin B.B.B is not a dead part reality of God particles rather it could connect itself with mind
part of reality to follow all orders made by CCP . Once the information’s ( Code PcPs- spin , velocity ,
directions , magnitude , type of red shift and blue shift etc ) are formed , the mass of Yin translates it and it
works accordingly .
Question on the nature of the particle wave. de Broglie and other scientists struggled to find out but failed. Ended in the probability interpretation.
September 2015, the LIGO detectors in the USA saw space vibrate with gravitational waves for the very first time. Although the signal was extremely weak when it reached Earth, it is already promising a revolution in astrophysics.
The theory of light that was stated by Imam Jaffar Sadiq(as) 1400 years ago. Imam Sadiq (as) was the grandson of Prophet Muhammad (as) and is the 6th holy Imam of the Muslims as followd by Shia Muslims
LECTURE 13. LIGHTHubble space telescope observations have tak.docxwashingtonrosy
LECTURE 13. LIGHT
Hubble space telescope observations have taken advantage of gravitational lensing to reveal the largest sample of the faintest and earliest known galaxies in the universe. Some of these galaxies formed just 600 million years after the Big Bang.
Space, mass, light and time are fundamental descriptors of our Universe. Captured by the poetry in Genesis, “In the beginning, when God created the heavens and earth, the earth was a formless wasteland, and darkness covered the abyss, while a mighty wind swept over the waters. Then God said “Let there be light,” and there was light.
The cosmological model of the “Big Bang” describes how the universe expanded from an initial state of very high density and high temperature. If observed conditions today areextrapolated backwards in time using the known laws of physics, the prediction is that our Universe emerged from a singularity, a point of infinite density, and that before this event, space and time did not exist.
Current knowledge is insufficient to determine if anything existed prior to the singularity. Sixteen centuries ago, in his Confessions, Saint Augustine (354-430) posed the obvious question in biblical terms: What was God doing before he created the Universe?
ISAAC NEWTON: COLOR SPECTRUM and the CORPUSCULAR THEORY of LIGHT
Our modern understanding of light and color begins with Isaac Newton (1642-1726) and a series of experiments that he published in 1672. He was the first to understand the rainbow. He refracted white light with a glass prism, resolving it into its component colors: red, orange, yellow, green, blue and violet.
In the graphic below, light enters the prism from the top right, and is refracted by the glass. The violet is bent more than the yellow and red, so the colors separate.
In the 1660s, Newton began experimenting with his “celebrated phenomenon of colors.” At the time, people thought that color was a mixture of light and darkness, and that prisms colored light. Hooke was a proponent of this theory of color, and had a scale that went from brilliant red, which was pure white light with the least amount of darkness added, to dull blue, the last step before black, which was the complete extinction of light by darkness. Newton believed this theory was false.
Newton set up a prism near a window at his boyhood home in Woolsthorpe, England ( site of the famous apple tree), and projected a beautiful spectrum 22 feet onto the far wall. Further, to prove that the prism was not coloring the light, he refracted the spectral light back together, producing white light. Incidentally, he was at home because all the students at Cambridge University where he was a student were sent home because of an epidemic of the bubonic plague. In 1665, it was a version of “social distancing.” BTW, Newton did his best work working from home.
On a personal note, my wife and I once visited the hometown of William Shakespeare (1564-1616), Stratford-upon-Avon..
On request from a friend - a journey that starts from Young's double split experiment and ends up with fundamental questions about the nature of reality and the essence of science...
WAVE-VISUALIZATION
1. Information gleaned from various sources. -“A BRIEF DESCRIPTION” - -Quantum physics is the physical theory that describes the behavior of matter, radiation and all their interactions views as both wave phenomena as either particle phenomena (wave-particle duality), unlike the classical Newtonian physics based on Isaac Newton's theories or, which sees for example the light just like wave and the electron just as a particle. ***In May 1926, Schrödinger proved that Heisenberg's matrix mechanics and his own wave mechanics made the same predictions about the properties and behaviour of the electron; mathematically, the two theories had an underlying common form. Yet the two men disagreed on the interpretation of their mutual theory. For instance, Heisenberg accepted the theoretical prediction of jumps of electrons between orbitals in an atom, but Schrödinger hoped that a theory based on continuous wave-like properties could avoid what he called (as paraphrased by Wilhelm Wien) "this nonsense about quantum jumps." The reconceived theory is formulated in various specially developed mathematical formalisms. In one of them, a mathematical function, the wave function, provides information about the probability amplitude of position, momentum, and other physical properties of a particle. Important applications of quantum mechanical theory include uperconducting magnets, light-emitting diodes and the laser, the transistor and semicoductors such as the microprocessor, medical and research imaging such as magnetic resonance imaging magnetic resonance and electron microscopy, and explanations for many biological and physical phenomena. Wave–particle duality is the fact that every elementary particle or quantic entity exhibits the properties of not only particles, but also waves. It addresses the inability of the classical concepts "particle" or "wave" to fully describe the behavior of quantum-scale objects. As Einstein wrote: "It seems as though we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully explains the phenomena of light, but together they do". The wave view did not immediately displace the ray and particle view, but began to dominate scientific thinking about light in the mid 19th century, since it could explain polarization phenomena that the alternatives could not
Introduction to Spectroscopy.pptx
this ppt provides the information on the introduction to spectroscopy and students can find the nots regarding spectroscopy.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Ethnobotany and Ethnopharmacology:
Ethnobotany in herbal drug evaluation,
Impact of Ethnobotany in traditional medicine,
New development in herbals,
Bio-prospecting tools for drug discovery,
Role of Ethnopharmacology in drug evaluation,
Reverse Pharmacology.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
Cambridge International AS A Level Biology Coursebook - EBook (MaryFosbery J...
Aristotle
1. Aristotle (384 - 322 B.C.), an ancient Greek thinker, thought that we saw the world by sending
“something” out of our eye and that reflected from the object.
In Plato’s time (427 – 347 B.C.), the reflection of light from smooth surfaces was known. He was also
a Greek.
The ancient Greeks (about 200 A.D.) also first observed the refraction of light which occurs at the
boundary of two transparent media of different refractive indices.
In the17th century, two scientists had different views about the nature of light ……
Isaac Newton cahaya sebagai partikel
1643 – 1727
Christian Huygens
1629 - 1695
Cahaya sebagai gelombang
In the 17th century, some properties of light were
well known already. For example:
Light has different colours.
Light can travel through a vacuum.
Light can be reflected and refracted, these processes are described by the Laws of Reflection and
Laws of Refraction.
According to the Laws of Reflection,
angle of incidence = angle of reflection (θi = θr )
Willebrord Snell discovered in 1621 that when a wave travels from a medium of refractive
index, n1 , to one of different refractive index, n2 ,
n1sin(θ1) = n2sin(θ2)
This relationship is called Snell’s Law
Light bends towards the normal when it travels from an optically less dense medium to an optically
more dense medium.
Newton proposed his “particle theory of light” (or “corpuscular theory of light”) to explain the
characteristics of light.
(source: “Opticks”, published by Isaac Newton in 1704)
I think light is a stream of tiny particles, called Corpuscles …
Particle Theory
2. Why does light have different colours?
The particles of different colours have different properties, such as mass, size and speed.
Why can light travel through a vacuum?
Light, being particles, can naturally pass through vacuum. (At Newton’s time, no known wave
could travel through a vacuum.)
Why does light travel in straight lines? A ball thrown into space follows a curved path
because of gravity.
Yet if the ball is thrown with greater and greater speed, its path curves less and less.
Thus, billions of tiny light particles of extremely low mass travelling at enormous speeds will
have paths which are essentially straight lines.
How does the particle theory explain the Laws of Reflection?
The rebounding of a steel ball from
a smooth plate is similar to the
reflection of light from the
surface of a mirror.
Many light
particles in a light ray
How does Newton's particle theory explain the Laws of Refraction?
A cannon ball hits the surface of water, it is acted upon by a “refracting” force which is
perpendicular to the water surface. It therefore slows down and bends away from the normal.
Light does the opposite. Newton explained this observation by assuming that light travels
faster in water, so it bends towards the normal.
(What was the problem in this explanation?)
The problem:
Does light really travel
faster in water?
In fact nobody could measure
the speed of light at the time of
Newton and Huygens
3. http://www1.fis.uc.pt/museu/optiNG.htm:
Newton thus described the nature of light as follows (the theory was closely linked to his mechanics):
it comprises corpuscles of different masses emitted by a source; these are propagated in space at a
tremendous velocity. When they reach the surface of a medium, these particles are acted upon by a
refracting force, excited by them, which is perpendicular to the surface and proportional to the
density of the affected body and acts at a short distance from it. This force, deflecting the trajectory of
the corpuscles, causes reflection, refraction, dispersion and what Grimaldi called diffraction.
Why does a prism separates a beam of white light into the colours of the rainbow?
Why does red light refract least and violet light refract most?
Newton’s assumptions:
1. The light particles of different colours have mass.
Red light particles have more mass than violet particles.
2. All light particles experience the same refracting force
when crossing an interface.
Thus, red light particles with more inertia will be refracted
less by the same force than violet light particles by the same force .
Let’s see how Huygens used his “wave theory” to explain the characteristics of light …
I think light is emitted as a series of waves in a medium he called “aether”
How do waves propagate? A wave starts at P and a “wavefront” W
moves outwards in all directions.
After a time, t, it has a radius r, so that
r = ct if c is the speed of the wave.
Each point on the wavefront starts
a secondary wavelet. These secondary
wavelets interfere to form a new wavefront
W’ at time t’.
How can wave theory explain the Laws of Reflection?
When wavefront W1 (AC) reaches point A, a secondary wave from A starts to spread out. When the
incoming wavefront reaches B, the secondary wave from A has reached D, giving a new wavefront W2
(BD).
4. Angle of incidence = Angle of reflection can be proved by geometry. Refer to the appendix of the
worksheet or your textbook for the proof.
How can wave theory explain the Laws of Refraction?
Wavefront W1 reaches the boundary between media 1 & 2, point A of wavefront W1 starts to spread
out. When the incoming wavefront reaches B, the secondary wave from A has travelled a shorter
distance to reach D. It starts a new wavefront W2. As a result the wave path bends towards the
normal.
n1sinθ1 = n2sinθ2
can be proved by geometry.
Refer to the appendix of the
worksheet or your textbook
for the proof.
If light behaves as waves, diffraction and interference should be seen. These are two important
features of waves. This was known in the 17th century.
(You can see this easily with water waves in a “ripple tank”)
The wave theory of light predicts interference and diffraction. However, Huygens could not
provide any strong evidence to show that diffraction and interference of light occurred.
The “ Laws of reflection” and the “Laws of refraction” are examples of laws. The “particle theory of
light” and the “wave theory of light” are examples of theories.
What is a scientific law?
What is a scientific theory?
What are the differences
between them?
Scientific laws are descriptions of relationships among phenomena or patterns in nature
5. What is a scientific law?
Scientific laws are descriptions of relationships among phenomena or patterns in nature
What is a scientific theory?
Scientific theories are the explanations of those relationships and patterns
The followings are definitions of a law and a theory.
Laws are generalizations, principles or patterns in nature. (McComas, 1998)
Laws are descriptive statements of relationships among observable phenomena. (Lederman et al.,
2002)
Theories are the explanations of those generalizations. (McComas, 1998)
Scientific theories are well-established, highly substantiated, internally consistent systems of
explanations.
(Suppe, 1977, cited in Lederman et al., 2002)
Law and theory
The Ideal Gas Law describes the relationships among P, V, and T of ideal gases.
Kinetic Theory explains these relationships (i.e. the Ideal Gas Law).
Scientific theories and laws are different kinds of knowledge. A theory will not turn into a law or vice
versa!
If you were one of the scientists in the 17th century, would you believe the “particle theory of light” or
the “wave theory of light”? Why?
Hint: Which theory has a greater ability to explain the characteristics of light?
Newton was the “winner”….. (at that time!)
Newton’s particle theory of light dominated optics during the 18th century.
Most scientists believed Newton’s particle theory of light because it had greater explanatory
power.
Let’s consider the reasons……
Waves do not travel only in straight lines,
so light cannot be “waves”.
Sounds can easily be heard around an obstacle but light cannot be seen around an obstacle.
Light, unlike sound, does not demonstrates the property of diffraction and it is unlikely to be a
type of wave.
6. (2) Light, unlike sound waves, can travel through a vacuum. Particles can travel through a
vacuum.
In the 17th century, it was believed that waves could not travel through a vacuum. It was
difficult for people at that time to believe that waves could travel through the “ether”, which
was the imaginary “medium” that light travels through, proposed by Huygens.
(3) Particle theory of light can explain why there are different colours of light.
Huygens could not explain why light has different colours at all. He did not know that different
colours of light have different “wavelengths”.
Though Newton’s explanation was not correct (particles of different colours of light have
different mass and size), his particles theory could explain this phenomenon logically in the
17th century.
(4) Reputation of Newton
People tend to accept “authority” when there is not enough evidence to make judgement.
Newton’s particle theory could only explain refraction by incorrectly assuming that light
travels faster in a denser medium. No one could prove he was wrong at that time.
The uncertainty about the speed of light in water remained unresolved for over one hundred
years after Newton's death.
Summary: From the debate over the nature of light between Huygens and Newton, we can learn that
…
Scientific laws are descriptions of patterns and phenomena of the nature. (e.g. Laws of
reflection, Laws of refraction)
Scientific theories are explanations of such patterns and phenomena. (e.g. particle theory of
light, wave theory of light)
A good theory should have strong explanatory power.
(Newton’s particle theory of light has a greater explanatory power than Huygens’ wave
theory of light.)
People tend to submit to authority when there is not enough evidence to make judgment.
(People believed Newton’s theory due to
his reputation in science.)
However, the wave theory of light was
re-examined 100 years after Newton’s particle theory of light had been accepted…… Light is not
particles! Thomas Young
1773 - 1829
7. Thomas Young successfully demonstrated the interference of light (which Huygens
failed to show), by his famous double-slit experiments.
Since then the wave theory of light has been firmly established.
The wave theory of light was widely accepted until 1905……
Wave theory of light? “No way!” Albert Einstein
1879 – 1955
The photoelectric effect is observed when light strikes a metal, and emits electrons.
Einstein used the idea of photons (light consists of tiny particles) to explain results which
demonstrate the photoelectric effect.
In the setup investigating the photoelectric effect (as shown below), the intensity of the light,
its frequency, the voltage and the size of the current generated are measured.
What evidence did Einstein find in his photoelectric effect experiments that helps to support
the particle theory of light?
Teaching notes: According to the wave theory, the strength / intensity of light is in proportion
to its brightness: a bright light should have been plenty strong enough to create a large
current.
Results from photoelectric effect experiments
For certain metals, dim blue light can generate a current while intense red light causes no
current at all.
Below a certain “cut off” frequency
of light ( ), no voltage is
measurable.
Why does the wave theory of light
not explain the result?
Einstein’s explanation
Electrons are knocked free from the metal by incoming photons, with each photon carrying an
amount of energy E that is related to the frequency (n) of the light by
E = h n
Where h is Planck’s constant (6.62 x 10-34 J seconds).
8. Only photons of high enough energy (above a threshold value) can knock an electron free. e.g.
blue light, but not red light, has sufficient energy to free an electron from the metal.)
Albert Einstein provided a piece of convincing evidence for the particle nature of light ……
Has the story ended yet?
Is light particles or waves?
Light is not particles, not waves, but BOTH! Louis de Broglie
1892 - 1987
Louis de Broglie in 1924 proposed that particles also have wave-like properties, this was
confirmed experimentally three years later.
Most scientists did not understand de Broglie’s Ph.D. dissertation at that time. One scientist
passed it on to Einstein for his interpretation. Einstein replied that de Broglie did not just
deserve a doctorate but a Nobel Prize!
De Broglie was awarded the
Nobel Prize in 1929.
Aristotle ( Light was emitted from our eyes )
Christian Huygens ( Wave theory of light )
Isaac Newton ( Particle theory of light )
Thomas Young ( Wave theory of light )
Albert Einstein ( Particle theory of light )
de Broglie ( Wave-particle duality of all matter)
Summary: What can we learn from the historical development about the understanding the nature of
light?
Evidence (e.g. Young’s double slit experiment, photoelectric experimental results…etc) can
establish or refute a theory.
Gathering scientific knowledge (the nature of light) is hard work, building upon the hard work
of other scientists in the past or present. (collaboration across time)
Scientific knowledge is ever changing, sometimes even revolutionary (Einstein discovered the
particle nature of light, de Broglie discovered the
wave-particle duality of all matter)