Not everything
that counts can be counted, and not everything that can be counted counts.
E=mc2
Learn how to survive World Year of Physics
So read the sign hung in the Princeton study of Albert Einstein, a man who knew
a thing or two about both. Einstein's face is already ubiquitous but will be
even harder to avoid this year because 2005 marks the centenary of the physicist
publishing three of his most famous ideas. The whole 12 months has been
designated Einstein Year and World Year of Physics to celebrate.
The most iconic images of Einstein show a scientist with his best work well
behind him. And it is the spirit of Einstein that scientists want to invoke, who
dropped out of school, failed his university entrance and was awarded a PhD
after submitting a thesis on spec; the Einstein who won the Nobel Prize and had
to give the money to his ex-wife as a divorce settlement. And this is the
Einstein who, while working in a patent office with a one-year-old baby at home,
hammered out a handful of theories that shook science to its foundations.
Einstein needed no laboratory or experiments to reach his conclusions, just time
to sit and think. Next time somebody catches you daydreaming, reply that you are
conducting a thought experiment, for which the physicist was famous. He left it
to others to test his ideas, rarely taking an interest in the results as he knew
which way they would fall. A century on, scientists still try to prove him
wrong.
So what are these ideas? Entire books have been written on the subject; some
have been finished and a few perhaps understood. The concepts involved are at
best esoteric and at worst very, very hard sums. A century after Einstein's
theory of special relativity was published, tyre company Pirelli is offering
25,000 to the person who has the best stab at getting it across. Relativity is
hardly likely to dominate pub conversation, but more than 11 months of Einstein
Year events remain ... which is a lot of shrugged shoulders and scratched heads
as familiar but impenetrable concepts crop up again. Think of this as a survival
guide. As the great man himself said:
"Everything should be made as simple as possible - but not simpler."
E=mc2
Einstein's most famous deduction and probably the easiest to understand. E is
energy, m represents mass and c is the speed of light, its a very big number
that becomes unimaginably huge when squared. On one level, it simply states that
even the smallest amounts of matter have the potential to release titanic
amounts of energy. On another, the equation is a product of special relativity
(see later) and predicts that energy and mass can be directly converted into one
another.
Special relativity
Take a deep breath. It all comes down to the speed of light. Einstein predicted
that (a) nothing could go faster and (b) it is always the same. The latter
sounds obvious, but picture a car speeding towards you at 50mph. If the driver
throws you a ball at 20mph, it will be ravelling at 70mph as you duck to avoid
it. But the speed of the light from the headlights that whizzes past you remains
constant, however fast the car travels.
Some slightly easier physics: speed is distance covered divided by time taken.
This is where it gets weird. If the speed of light never changes, then distance
and time must. Weirder still, Einstein says this means that as an object moves,
it shrinks in the direction of its motion. Beyond weird, the same movement slows
down time. It sounds crazy but the maths adds up.
Still reading? The key to understanding relativity is being able to see someone
else's viewpoint. The changes in length and in time are only noticeable when
seen from a different view, or frame of reference. The car driver, for example,
would see the ball travelling at 20mph away from him, because he is already
moving at 50mph. And the ball would see the driver moving away from him at
20mph, while you sped towards it at 70mph.
It's all relative.
Pub bluff: Probably best to say something about how the terrible destruction
wreaked by the Hiroshima and Nagasaki atomic bombs was caused by energy released
by just a fraction of the uranium mass and move on.
Pub bluff: "Einstein moved from little-known physicist to international
celebrity in 1919 when observations during a solar eclipse proved the sun bent
light from distant stars."
Pub bluff: "Einstein wrote out a replica of his original 1905 special relativity
paper for auction and raised $6m for the US war effort in 1944."
Time and the man
1879: Albert Einstein born on March 14 in Ulm, Germany
1905: Has annus mirabilis (miracle year). Publishes four papers that set bedrock
for modern physics - while working in the patent office in Bern. Completes
theory of general relativity in 1915
1922: Awarded Nobel Prize for physics
1933: Moves to Institute for Advanced Study in Princeton after Nazis take power
in Germany
1952: Turns down offer to become President of Israel
1955: Dies on April 18 of ruptured abdominal aorta. Brain removed for study 1955
A Party of Famous Physicists
One day, all of the world's famous physicists decided to get together for a
tea luncheon. Fortunately, the doorman was a grad student, and able to observe
some of the guests...
Everyone gravitated toward Newton, but he just kept moving around at a
constant velocity and showed no reaction.
Einstein thought it was a relatively good time.
Cavendish wasn't invited, but he had the balls to show up anyway.
Cauchy, being the only mathematician there, still managed to integrate well
with everyone.
Pauli came late, but was mostly excluded from things, so he split.
Pascal was under too much pressure to enjoy himself.
Ohm spent most of the time resisting Ampere's opinions on current events.
Volt thought the social had a lot of potential.
Heisenberg may or may not have been there.
The Curies were there and just glowed the whole time.
de Broglie mostly just stood in the corner and waved.
Everyone was attracted to Tesla's magnetic personality.
Bohr ate too much and got atomic ache.
Watt turned out to be a powerful speaker.
Hertz went back to the buffet table several times a minute.
Faraday had quite a capacity for food.
Oppenheimer got bombed.
You Might be a Physics Major...
...if you have no life - and you can PROVE it mathematically.
...if you enjoy pain.
...if you know vector calculus but you can't remember how to do long division.
...if you chuckle whenever anyone says "centrifugal force."
...if it is sunny and 70 degrees outside, and you are working on a computer.
...if you frequently whistle the theme song to "The X-Files."
...if you always do homework on Saturday nights.
...if you know how to integrate a chicken and can take the derivative of water.
...if you hesitate to look at something because you don't want to break down its
wave function.
...if you have a pet named after a scientist.
...if you laugh at jokes about mathematicians.
...if you can translate English into Binary.
...if you can't remember what's behind the door in the science building which
says "Exit."
...if you have to bring a jacket with you, in the middle of summer, because
there's a wind-chill factor in the lab.
...if you consider ANY non-science course "easy."
...if the "fun" center of your brain has deteriorated from lack of use.
...if you'll assume that a "horse" is a "sphere" in order to make the math
easier.
Kid's Views on Science
The beguiling ideas about science quoted here were gleaned from essays, exams,
and class room discussions; most were from fifth- and sixth-graders. They
illustrate Mark Twain's contention that the "most interesting information comes
from children, for they tell all they know and then stop."
Q: What is one horsepower?
A: One horsepower is the amount of energy it takes to drag a horse 500 feet in
one second.
You can listen to thunder after lightening and tell how close you came to
getting hit. If you don't hear it you got hit, so never mind.
When they broke open molecules, they found they were only stuffed with atoms.
But when they broke open atoms, they found them stuffed with explosions.
When people run around and around in circles we say they are crazy. When planets
do it we say they are orbiting.
While the earth seems to be knowingly keeping its distance from the sun, it is
really only centrificating.
Most books now say our sun is a star. But it still knows how to change back into
a sun in the daytime.
A vibration is a motion that cannot make up its mind which way it wants to go.
Many dead animals of the past changed to fossils, others preferred to be oil.
Vacuums are nothings. We only mention them to let them know we know they're
there.