is physics a coherent body of useful contemporary knowledge? or… only a method of inquiry...

Is Physics a coherent body of useful contemporary knowledge? Or…

only a Method of Inquiry unchanged since the Age of Enlightenment?

What should be the public awareness of Physics?

Intro. Phys. I – to American RevolutionIntro. Phys. II – to American Civil WarModern Phys. – to the Great Depression

Relearning the ignorance of the “Enlightenment”

Planetary motion (Copernicus, Galileo, Brahe, Kepler 1500-1600)

Newton’s laws (Newton 1687)

Electricity (Coulomb 1777)

Magnetism (Oersted 1819)

Kinetic theory (Maxwell 1860)

Relativity E&M (Voigt 1887)

Atomic confirmation (Einstein 1905)

Line spectra (Kirchhoff 1859)

‘the concept of force has reached the end of its life cycle …(suggesting) its disbarment from the inventory of fundamentalconcepts in physics.’

Max Jammer, Concepts of Force, 1957

‘In all methods and systems which involve the idea of force there isa leaven of artificiality… there is no necessity for the introduction of the word “force” nor the sense-suggested ideas on which it was originally based.” Peter G. Tait, Dynamics, 1895

‘If people were to learn to conceive the world in a new way, without the old notion of “force,” it would alter not only their physical

imagination, but probably also their morals and politics.’ Bertrand Russell, The ABC of Relativity, 1925

Quotes from Force-Trained students:

‘How can a rocket work in outer space where there is nothing for the force to push on?’

‘The moon doesn’t fall to earth because the centrifugal force holds it out.’

‘We know that nuclei are small because -projectiles miss them and go mainly forward. If nuclei were large, -particles would hit them, feel a force, and bounce backward.’

‘If weight is gravitational force, and orbiting astronauts are weightless, then they must be outside the range of gravity.’

Are the problems we assign even realistic?

1. Viscous drag nonlinearly couples horizontal & vertical – solve numerically.

2. Aerodynamics of backspin dominates the range achieved.

Am. J. Phys. 71, 1152 (2003); dispute / R.K. Adair 73, 184 (2005).

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A lousy approximation!

THE NATURE OF MATTER_________________________________________________________

All matter consists of little bits of positive and negative electricity:in perpetual motion;attract each other at short distances;repel each other when pressed too close together.

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The most important discovery ever made.If all other scientific information we know were lost in some

cataclysmic event, and only this information survived, all could be rediscovered in a very short time.

  - Richard P. Feynman`

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(Ohio State Board of Education –12/10/02)

Iron atoms positioned on a carbon surface

Second Quantization - The Discrete Photon

700 keV Li+ beam (v=4.4 mm/ns) incident on a thin (3 g/cm2) carbon foil.

The blue light is H-like 4f-5g in Li2+ (4500Å, =3 ns, x=1.3 cm). The green light is He-like 2s 3S-2p 3P in Li+ (5485Å, =44 ns, x=19 cm).

Can we pictureattractive and repulsive interactions

without the force concept?

Quantum Field Theory is conceptually easy!

ACTION-AT-A-DISTANCEExchange of a ‘gauge boson’

Particle exchange can produce both attraction and repulsion.

It is intermittent, like rain on the roof. The Force concept requires an average over a time interval.

Nature has revealed a beautiful secret!

The behavior of the Universe becomes very simple if it is described in a way in which space and time are symmetric.

What makes it seem hard, is the fact the we must liveour lives by standing at a point in space and watchingtime pass, but not the reverse.

It’s like our perspective in riding the Earth around the Sun, which seems as if the Sun were going around us.However, the heliocentric equations are much simpler.

TIME

“Time is what keeps everything from happening at once.” - Attributed to John Archibald Wheeler

Quoted by Woody Allen

“Time flies like an arrow; fruit flies like a banana.” - Groucho Marx

‘Backward turn, turn backward, O time in your flight. Make me a child again, just for tonight.’ - Elizabeth Akers Allen

Electron-positron pair production

The “photon-dressed” electron

Electron-Positron PairCreation and Annihilation

Once created, e+ and e- are stable until annihilated

Past

Future

Here-Now

Are they all reallythe same electron?

time

space

Why didn’t Isaac Newton think about the possibility ofgetting hit on the head when he sat under the apple tree?

x

Where does the pendulum spend the most time? The least time?

Dwell time:

High: many / slow

Low: Few / fast

Time exposure

Equal time insideNo time outside

Most time at end points Least time at center

Most time at aphelion and perihelion

The secret of life, computers, & transitors

Laplacian Determinacy – A Costly Mistake

Pierre Simon Laplace - 1776: “An intelligence that knows all of the relations of the entities of the universe at one instant could state theirpositions, motions, and general effects any instant in the past of future.

Henri Poincare – 1903: “Small differences in the initial conditions can produce very great ones in the final phenomena – prediction Then becomes impossible (1st recognition of chaos).

Werner Heisenberg – 1924: There is a fundamental limit on the accuracy to which position and velocity can be co-determined.

Stephen Hawking –1988: In the cosmology of the Big Bang and Black Holes, space and time themselves break down.