If you have the chance, you can post your project, assignment or whatever here, so that other members can easily come and look for help here if they need it.
[I got to double post cause this one is for the rules etc. I will update this post soon with it etc.]
I'll start.
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School Work Post your essays, projects, assignments.
#1
- Master Adept
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- Group: Veterans
- Posts: 8,895
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AKA YouTube Dude
Posted 21 May 2005 - 04:23 PM
#2
- Master Adept
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- Group: Veterans
- Posts: 8,895
- Joined: 28-January 04
- Gender:Male
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AKA YouTube Dude
Posted 21 May 2005 - 04:28 PM
Subject: Physics
Project: The nature of Light
Objective: To compare and contrast the rival theories of light.
Help:Teacher gave us the 4 scientists - Isaac Newton, Thomas Young, Albert Einstein & Christiaan Huygens.
Introduction
The scientific study of the behaviour of light is called optics and covers reflection of light by a mirror and other object, refraction by a lens and prism, diffraction of light as it passes by the edge of an opaque object, and interference patterns resulting from diffraction and the polarisation of light. Any successful theory of the nature of light must be able to explain these and other optical phenomena.
Since the start of time humans have had many theories on how and what light consists of; ancient philosophers like Aristotle thought man saw by sending something of an unknown origin from our eyes and it reflected back. At the end of the seventh century there were two conflicting views of light, was it a phenomenon caused by waves or a particle phenomenon? Thanks to Isaac Newton’s experiments that showed light was made up of particles therefore the wave theory was completely wrong while the corpuscular theory was correct, or was it?
For more than 100 years, Newton's corpuscular theory was favoured over the wave theory of light, eventually later important experiments were done on the diffraction and interference of light by Thomas Young in 1801 that could only be interpreted in terms of the wave theory. The polarisation of light was yet another phenomenon that could only be explained by the wave theory. This project will discus the rival theories, their united form - and come to a final conclusion.
The Light Theories
Particle Nature - Corpuscular Theory
Isaac Newton originally thought light travelled as small particles called corpuscles (particles of matter) that travelled through space. He also thought that corpuscles travelled in straight lines. Light as particles explained how shadows and reflections are formed, as well as refraction and how light can change its speed when passing through different materials. To demonstrate reflection, Newton's particle model compared a ball bouncing off a mirror to particles being reflected.
Corpuscular Theory states:
1) An opaque object in the path of a beam of light casts a sharp shadow. Particles travelling in straight lines would be expected to do just this.
2) Light can travel through a vacuum. Whilst there was obviously no difficulty with the idea of particles travelling thorough a vacuum, there was with waves (at this time no known wave could).
Setback of the Corpuscular Theory:
1) Newton had trouble explaining diffraction, interference and colour using the corpuscular theory.
Photons Theory
Albert Einstein proposed that the energy of radiation was in discrete packets. Each packet of light energy is called a photon.
The Wave Nature – Huygens Wave Theory
Christiaan Huygens suggested that light travelled as waves to combat Newton’s Corpuscular theory. A few centuries later Thomas Young produced evidence of the wave nature of light, this was the blow against the particle theory. Huygens stated that an expanding sphere of light behaves as if each point on the wave front were a new source of radiation of the same frequency and phase
Setback of Huygens Wave Theory:
Could not explain colours so his theory was not accepted.
Young Wave Theory
In 1801 Thomas Young took Huygens theory of light as waves and proved what Huygens couldn’t stated each coloured light possessed its own wave length. Young went on to show white light can be separated into different colours. This was what crushed Newton’s corpuscular theory. He also proposed that when two light beams interact they create interference which can be constructive or destructive. The places where constructive and destructive interference occur are subjected to constant change, since electromagnetic waves emitted are capable of varying phase. Using one light source and splitting it into two beams you can create two coherent sources, meaning they are of identical frequencies and have a constant phase difference. This was all explained using the Double Slit experiment.
Experiment: Young’s double slit
A light bulb, or lamp can be used, but the light must be reduced to a monochromic source with filters and must be coherent, screens with two very thin identical slits and a screen to view the interference on. When the light is switched on, it travels up to the first screen and is split into two beams by the slits, when this happens waves are diffracted and bulge outwards causing two curved wave fronts to propagate the other side of the slits, at many places between the slits and the viewing screen there are areas of constructive interference and by moving the viewing screen it is possible to get a picture of where they are occurring. When the extra distance covered by the top wave is the same as the wavelength of the light two peaks will meet at a point on the screen thus creating constructive interference.
Quantum Theory
The quantum theory is also known as the wave-particle light theory duality. This theory states that light behaves as both a particle and a wave at certain circumstances. This is the theory modern day physics use.
Conclusion
After doing this project, we have come to a conclusion that both theories are acceptable and have flaws. We have also observed that phenomena that the particle theories couldn’t of explain the wave theory’s did and vice versa. We also saw how effective it was to combine both theories. All in all the nature of light still puzzles man today.
This project isn't completed, I just thought I'd start it of with one of mines, its due next week. It also had a 3 page limit on MS Word.
Project: The nature of Light
Objective: To compare and contrast the rival theories of light.
Help:Teacher gave us the 4 scientists - Isaac Newton, Thomas Young, Albert Einstein & Christiaan Huygens.
Introduction
The scientific study of the behaviour of light is called optics and covers reflection of light by a mirror and other object, refraction by a lens and prism, diffraction of light as it passes by the edge of an opaque object, and interference patterns resulting from diffraction and the polarisation of light. Any successful theory of the nature of light must be able to explain these and other optical phenomena.
Since the start of time humans have had many theories on how and what light consists of; ancient philosophers like Aristotle thought man saw by sending something of an unknown origin from our eyes and it reflected back. At the end of the seventh century there were two conflicting views of light, was it a phenomenon caused by waves or a particle phenomenon? Thanks to Isaac Newton’s experiments that showed light was made up of particles therefore the wave theory was completely wrong while the corpuscular theory was correct, or was it?
For more than 100 years, Newton's corpuscular theory was favoured over the wave theory of light, eventually later important experiments were done on the diffraction and interference of light by Thomas Young in 1801 that could only be interpreted in terms of the wave theory. The polarisation of light was yet another phenomenon that could only be explained by the wave theory. This project will discus the rival theories, their united form - and come to a final conclusion.
The Light Theories
Particle Nature - Corpuscular Theory
Isaac Newton originally thought light travelled as small particles called corpuscles (particles of matter) that travelled through space. He also thought that corpuscles travelled in straight lines. Light as particles explained how shadows and reflections are formed, as well as refraction and how light can change its speed when passing through different materials. To demonstrate reflection, Newton's particle model compared a ball bouncing off a mirror to particles being reflected.
Corpuscular Theory states:
1) An opaque object in the path of a beam of light casts a sharp shadow. Particles travelling in straight lines would be expected to do just this.
2) Light can travel through a vacuum. Whilst there was obviously no difficulty with the idea of particles travelling thorough a vacuum, there was with waves (at this time no known wave could).
Setback of the Corpuscular Theory:
1) Newton had trouble explaining diffraction, interference and colour using the corpuscular theory.
Photons Theory
Albert Einstein proposed that the energy of radiation was in discrete packets. Each packet of light energy is called a photon.
The Wave Nature – Huygens Wave Theory
Christiaan Huygens suggested that light travelled as waves to combat Newton’s Corpuscular theory. A few centuries later Thomas Young produced evidence of the wave nature of light, this was the blow against the particle theory. Huygens stated that an expanding sphere of light behaves as if each point on the wave front were a new source of radiation of the same frequency and phase
Setback of Huygens Wave Theory:
Could not explain colours so his theory was not accepted.
Young Wave Theory
In 1801 Thomas Young took Huygens theory of light as waves and proved what Huygens couldn’t stated each coloured light possessed its own wave length. Young went on to show white light can be separated into different colours. This was what crushed Newton’s corpuscular theory. He also proposed that when two light beams interact they create interference which can be constructive or destructive. The places where constructive and destructive interference occur are subjected to constant change, since electromagnetic waves emitted are capable of varying phase. Using one light source and splitting it into two beams you can create two coherent sources, meaning they are of identical frequencies and have a constant phase difference. This was all explained using the Double Slit experiment.
Experiment: Young’s double slit
A light bulb, or lamp can be used, but the light must be reduced to a monochromic source with filters and must be coherent, screens with two very thin identical slits and a screen to view the interference on. When the light is switched on, it travels up to the first screen and is split into two beams by the slits, when this happens waves are diffracted and bulge outwards causing two curved wave fronts to propagate the other side of the slits, at many places between the slits and the viewing screen there are areas of constructive interference and by moving the viewing screen it is possible to get a picture of where they are occurring. When the extra distance covered by the top wave is the same as the wavelength of the light two peaks will meet at a point on the screen thus creating constructive interference.
Quantum Theory
The quantum theory is also known as the wave-particle light theory duality. This theory states that light behaves as both a particle and a wave at certain circumstances. This is the theory modern day physics use.
Conclusion
After doing this project, we have come to a conclusion that both theories are acceptable and have flaws. We have also observed that phenomena that the particle theories couldn’t of explain the wave theory’s did and vice versa. We also saw how effective it was to combine both theories. All in all the nature of light still puzzles man today.
This project isn't completed, I just thought I'd start it of with one of mines, its due next week. It also had a 3 page limit on MS Word.
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