The wave and particle theory of light

[Ostronomos]

The ancient Greeks as I explained, are responsible for much of what we call modern science. They've given us a premature concept of atomism, the elements and even visual perception, which was proven to be false when the Arab influences in the 11th century, gave us a better understanding of lenses and mirrors.

Sir Isaac Newton and Christian Huygens competed for the wave versus particle theory of light. But it was Thomas Young (born circa 1773) who, in the first double slit experiment, established the wave theory to be correct. Thomas Young was a wealthy doctor who turned his mind to everything from the elasticity of materials to deciding on insurance premiums. He was a notable figure in History.

 

[Subduction Zone]

The ancient Greeks as I explained, are responsible for much of what we call modern science. They've given us a premature concept of atomism, the elements and even visual perception, which was proven to be false when the Arab influences in the 11th century, gave us a better understanding of lenses and mirrors.

Sir Isaac Newton and Christian Huygens competed for the wave versus particle theory of light. But it was Thomas Young (born circa 1773) who, in the first double slit experiment, established the wave theory to be correct. Thomas Young was a wealthy doctor who turned his mind to everything from the elasticity of materials to deciding on insurance premiums. He was a notable figure in History.

And I do believe that it was Einstein that showed that Young was not quite right and that light is a particle too. There may have been a Nobel Prize involved with it.

 

[syo]

The ancient Greeks as I explained, are responsible for much of what we call modern science. They've given us a premature concept of atomism, the elements and even visual perception, which was proven to be false when the Arab influences in the 11th century, gave us a better understanding of lenses and mirrors.

Sir Isaac Newton and Christian Huygens competed for the wave versus particle theory of light. But it was Thomas Young (born circa 1773) who, in the first double slit experiment, established the wave theory to be correct. Thomas Young was a wealthy doctor who turned his mind to everything from the elasticity of materials to deciding on insurance premiums. He was a notable figure in History.

It's an ugly world, isn't it?

 

[exchemist]

The ancient Greeks as I explained, are responsible for much of what we call modern science. They've given us a premature concept of atomism, the elements and even visual perception, which was proven to be false when the Arab influences in the 11th century, gave us a better understanding of lenses and mirrors.

Sir Isaac Newton and Christian Huygens competed for the wave versus particle theory of light. But it was Thomas Young (born circa 1773) who, in the first double slit experiment, established the wave theory to be correct. Thomas Young was a wealthy doctor who turned his mind to everything from the elasticity of materials to deciding on insurance premiums. He was a notable figure in History.

Why stop there? The story continues, as @Subduction Zone points out, with Einstein and the photo-electric effect, for which he got his Nobel Prize, which showed that light comes in discrete chunks or particles that he called "quanta", thus kicking off quantum theory. So the actual end of the story (at least, so far) is that both Newton and Young seem to have been half-right, according to modern physics.

 

[idea]

F = m a = d(mv)/dt = v (dm/dx)(dx/dt)
= v^2 (dm/dx)

Fdx = v^2 m

So... what does constant velocity mass flow rate have to do with it? v^2 m, c^2 m

PV = Fdx = v^2 (V*density)
P = v^2 density. Perhaps Bernoulli was onto something?

 

[exchemist]

F = m a = d(mv)/dt = v (dm/dx)(dx/dt)
= v^2 (dm/dx)

Fdx = v^2 m

So... what does constant velocity mass flow rate have to do with it? v^2 m, c^2 m

PV = Fdx = v^2 (V*density)
P = v^2 density. Perhaps Bernoulli was onto something?

What does any of this have to do with anything? Even the algebra doesn't seem to make sense.

 

[Polymath257]

F = m a = d(mv)/dt = v (dm/dx)(dx/dt)
= v^2 (dm/dx)

Fdx = v^2 m

So... what does constant velocity mass flow rate have to do with it? v^2 m, c^2 m

PV = Fdx = v^2 (V*density)
P = v^2 density. Perhaps Bernoulli was onto something?

You are assuming velocity is constant with time, but that mass changes?

 

[Polymath257]

Why stop there? The story continues, as @Subduction Zone points out, with Einstein and the photo-electric effect, for which he got his Nobel Prize, which showed that light comes in discrete chunks or particles that he called "quanta", thus kicking off quantum theory. So the actual end of the story (at least, so far) is that both Newton and Young seem to have been half-right, according to modern physics.

And go past Einstein to Feynman and QED. And don't forget the earlier stages of Maxwell, after unifying electromagnetism.

There is a fascinating book that tells the story of the history of ideas about light: "The Fire Within the Eye". Well worth the read.

 

[exchemist]

You are assuming velocity is constant with time, but that mass changes?

In other words that a=0, so F=0 and the whole thing becomes an exercise in 0=0.

 

[idea]

You are assuming velocity is constant with time, but that mass changes?

Correct. From fluid in a pipe, to air through helicopter blades or snow blower - mass flowing at constant velocity.

Light has a constant velocity too, just kind of an interesting result, that constant velocity mass flow rates take on the same equation as E = m c^2.

 

[idea]

In other words that a=0, so F=0 and the whole thing becomes an exercise in 0=0.

F is not 0.
It's a simple chain rule, high school math and understanding of physics

 

[exchemist]

F is not 0.
It's a simple chain rule, high school math and understanding of physics

F = ma implies that if a = 0, F= 0.

If v is changing with time, the first line of your algebra is wrong, because you can't then take v outside the differential with respect to t, as you have done. To do that, v must not vary with time, in which case a=0.... and thus F=0.

 

[idea]

F = ma implies that if a = 0, F= 0.

If v is changing with time, the first line of your algebra is wrong, because you can't then take v outside the differential with respect to t, as you have done. To do that, v must not vary with time, in which case a=0.... and thus F=0.

Newton's law is actually that force is the rate of change of momentum with time,
F=d(mv)dt.
Therefore,
F=mdv/dt+vdm/dt
For a constant velocity, the force is created by the rate of change of mass = vdm/dt. You can Google it, mass flow rates.

 

[exchemist]

Newton's law is actually that force is the rate of change of momentum with time,
F=d(mv)dt.
Therefore,
F=mdv/dt+vdm/dt
For a constant velocity, the force is created by the rate of change of mass = vdm/dt. You can Google it, mass flow rates.

A mass flow rate is just the rate at which mass in motion, say air flowing in a pipe, passes a given point.

But I really can't follow where you are going with this. The thread is about light: the wave aspect and the particle aspect. As light is massless, what relevance does mass flow rate have to the thread subject?

 

[idea]

A mass flow rate is just the rate at which mass in motion, say air flowing in a pipe, passes a given point.

But I really can't follow where you are going with this. The thread is about light: the wave aspect and the particle aspect. As light is massless, what relevance does mass flow rate have to the thread subject?

Here's the derivation - it's one of those crazy things, like similarities between kqq/r^2 and GMm/r^2. - one of those weird things -

F = v *dm/dt = v (dm/dx)(dx/dt) chain rule, just multiply it by dx/dx, multiply by 1. So dx/dt = v, and you get your v^2.

F = v^2 (dm/dx)

Bring dx over, then integrate
Fdx = m v^2 = energy

Turns out that E = m c^2 equation works for more than just light. It works for any constant velocity mass flow problem, works in the classical Newtonian world as well as quantum world.

E = m v^2 also extrapolates to the core of Bernoulli's equation.

The laws of the universe are written with math, and somewhere within it all is a unifying equation.

 

[exchemist]

Here's the derivation - it's one of those crazy things, like similarities between kqq/r^2 and GMm/r^2. - one of those weird things -

F = v *dm/dt = v (dm/dx)(dx/dt) chain rule, just multiply it by dx/dx, multiply by 1. So dx/dt = v, and you get your v^2.

F = v^2 (dm/dx)

Bring dx over, then integrate
Fdx = m v^2 = energy

Turns out that E = m c^2 equation works for more than just light. It works for any constant velocity mass flow problem, works in the classical Newtonian world as well as quantum world.

E = m v^2 also extrapolates to the core of Bernoulli's equation.

The laws of the universe are written with math, and somewhere within it all is a unifying equation.

E = mc² does not work for light.

Consider these two questions:

1) Does a photon have energy?

2) What is the rest mass of a photon?

And then look again at that formula.

 

[Subduction Zone]

E = mc² does not work for light.

Consider these two questions:

1) Does a photon have energy?

2) What is the rest mass of a photon?

And then look again at that formula.

Will he get it? Photons are weird. Their "frequency" (that raises another question, how does a single photon have a frequency?) depends on the relative motion between source and receiver. That just shows that classical physics has limits in its ability to explain.

 

[exchemist]

Will he get it? Photons are weird. Their "frequency" (that raises another question, how does a single photon have a frequency?) depends on the relative motion between source and receiver. That just shows that classical physics has limits in its ability to explain.

Let's see.

 

[idea]

E = mc² does not work for light.

Consider these two questions:

1) Does a photon have energy?

2) What is the rest mass of a photon?

And then look again at that formula.

I'm not sure what your educational background is? Try this as a starter
Mass–energy equivalence - Wikipedia

 

[Subduction Zone]

I'm not sure what your educational background is? Try this as a starter
Mass–energy equivalence - Wikipedia

Probably better than yours. Why didn't you answer?