Physics Video Quiz Number 3

What two new forces were discovered in the study of atomic structure.

"Strong nuclear force" and "weak nuclear force"

How many dimensions does string theory predict?

11

How many constants determine the nature of the universe?

20 fundamental constants of nature give the universe its characteristics.

How many equations did Maxwell need?

4 elegant mathematical equations that unified electromagnetism in a single force

If an atom were made as large as the solar system, how large would a string be?

As large as a tree.

What happened to Einstein's quest upon his death?

At first, no advances were made. His quest was not engaged by other physicists. Then scientists split, one group studied general relativity and the other group used quantum mechanics.

What would happen if the electromagnetic force were made stronger?

Atoms repel each other more strongly. The nuclear furnace of the sun would go out, stars would fizzle out, and the universe as we know it disappears.

What are examples of things that happen in the quantum world that do not happen in every day life?

Big things act as though they are tiny. Definite orders do not apply. Everything is ruled by chance. There would be only a probability of getting an orange juice. There is only a chance that the impossible can happen. Objects can pass through another solid object.

How does Bronowski view the 1930's?

Bronowski views the 1930s as a time in which a crucial confrontation of culture, the ascent of man, against the throwback of despotic belief to the notion of absolute certainty.

Who was the other famous public figure when Einstein became a prominent figure in the news?

Charlie Chaplin.

Why is a black hole a theoretical challenge for physicists today?

Do you use general relativity or quantum mechanics to understand black holes? Since black holes are both tiny and heavy, both theories have to be used. However, when you try to use both theories together, the results are chaotic and nonsensical. The universe has to be sensible.

How do gravity and EM compare in strength? What evidence exists to support this idea?

EM is a billion times stronger than gravity. They are very different in strength, to the point that the difference outweighs their similarities. Outer shell of every atom contains a negative electrical charge, charges repels each other and can stop an object from falling.

What two forces did Einstein first try to unite? Why did he start with only two of the four forces in nature?

Einstein tried to unite gravity with electromagnetism. They were the only two forces in nature known at the time.

How was Bohr's physics different from Einstein's?

Eintsein's physics demanded that the universe is orderly and predictable. Bohr disagreed. At the atomic or quantum level, uncertainty rules. The best you can do according to quantum mechanics is predict the chance or probability of one outcome or another.

What unification did Maxwell achieve?

Electricity and magnetism

What force makes concrete hard?

Electromagnetism

What happens to our understanding of the universe when we run the history of the universe backwards?

Everything that's rushing apart comes back together. The universe gets smaller, hotter, and denser as we head back to the beginning of time.

What forces does the standard model unite?

Everything was converging to a simple picture of the known particles and forces. This picture became the standard model. It describes all interacts (weak force, strong force, electromagnetic) in the same language.

How do experimental observations compare to the predictions of quantum theory?

Experimental observations have supported predictions of quantum theory. There has never been a contradiction.

What did Gauss learn from the study of the error in observations?

Gauss asked what the scatter of the errors tells us. The scatter marks an area of uncertainty. We are not sure that the true position is the center all we can say that it lays in an area of uncertainty.

How does the quantum view of space differ from that of general relativity?

General relativity: deals with big things - how gravity works. It pictures space as a sort of trampoline that has a smooth fabric that heavy objects like stars and planets can warp and stretch. These warps and curves create what we feel known as gravity. It is predictable. Quantum mechanics: deal with small things like atoms and particles. The view of the structure of Space is far less structured. The fabric of space becomes bumpy and chaotic. It is turbulent and defies common sense. The fluctuating jittery picture of space and time predicted by quantum mechanics is in direct conflict with the smooth orderly geometric model of space and time of described by general relativity.

What role did Max Born have in the development of atomic theory?

He began a series of seminars which brought everyone interested in atomic physics to them. Born drew young men to him, got the best out of them, and the ideas they exchanged produced his best work. Van Heisenburg did his finest work with Born. Arguments took place at these seminars.

What did Einstein think about the probability of quantum theory?

He never lost faith that the universe behaves in a certain and predictable way. He resisted quantum theory. "God does not throw dice."

Why is it said that Einstein became isolated from physics?

He stopped reading other people's papers. He chooses not to look at the physics coming from these experiments. Quantum mechanics had no role in his work.

Why did Szilard keep his patent a secret?

He wanted to prevent science from being misused, did not want it to be published until after the war.

What did Newton unify?

Heavens and the earth in the theory of gravity.

Under what circumstances would string theory be philosophy instead of science?

If there's no evidence or prediction for them, strings are not a theory, and so they cannot be science (and they would only be philosophy).

How does a cable give a clue to unseen dimensions?

If we get closer, we can see a new dimension we are unable to see when we are far away.

What famous realization came to Szilard while waiting for a traffic light?

If you hit an atom with one neutron and it breaks up into at least two atoms, you would have a chain reaction.

Why is string theory a paradigm shift?

Instead of billiard balls, we have to use strands of spaghetti.

What idea did Suskin try to publish?

Introducing the idea of strings.

How does string theory solve the jitter problem at the quantum level?

It calms the jitters of quantum mechanics, spreads them out by virtue of taking a point particle and spreading it out into a string. It resolves both quantum mechanics and general relativity.

What did resolution of anomalies allow string theory to do?

It had the mathematical depth to encompass all four forces (unification of different forces: weak, strong, electromagnetic, and gravity).

What were the early problems with string theory?

It predicted a particle that is unphysical - a particle that traveled faster than light. It predicted and required there be 10 dimensions. It had a massless particle that was not seen in experiments, and it had anomalies.

What did Veneziano discover about Euler's equation?

It seemed to describe the strong force.

What does string theory unite?

It unites the theory of large and small, different forces and particles (general relativity and quantum mechanics). It proclaims all forces and matter are made of strings.

When were black holes first predicted? Who made the prediction? What was this scientist doing when he made these calculations?

Karl Schwarzschild in 1916. He was stationed on the front lines in World War I.

What new physics began in the 20's ? What effect did this have on Einstein's mathematical methods?

Led by Bohr, a team of scientists were beginning quantum mechanics. Old theories of Einstein and Maxwell were inadequate and insufficient and cannot explaining the bizarre ways the tiny bits of matter interacted with one another inside the atom.

How much attention did Einstein give to the weak force?

Little to none.

What are the two kinds of dimensions?

Long and unfurled ---like length of steel cable. Tiny and curled up ---like the circular motion wrapped around the cable.

What does mass do to space-time?

Mass makes space-time curve and warp. Its this warping or curving that creates what we feel as gravity.

What mystery remained about Newton's theory of gravity?

Newton had no idea how gravity worked. Newton thought that gravity acted instantaneously across any distance. But it cannot because light takes time to travel, and gravity cannot travel faster than light.

How did this idea about light relate to gravity?

Not even gravity can travel faster than light. So how could the earth go faster than the light from the sun?

What was the riddle of the behavior of the electron?

On Mondays, Wednesdays, and Fridays, it would behave like a particle. On Tuesdays, Thursday and Saturdays it would behave like a wave. How could you match those two aspects brought from the large scale world into a small entity in the atom?

How does the size of the observable detail compare to the wavelength used?

Only shorter wavelengths will allow any fraction of detail to appear. We should be able to see the violet (shorter) waves better than the red (longer) waves.

What two theories does string theory hope to unite?

Quantum mechanics and general theory of relativity.

What does string theory suggest about quarks?

Quarks are not the smallest things. There are even smaller parts called strings.

Why does Bronowski mean when he says that physics is philosophy?

Quote from Born's autobiography: "I am now convinced that theoretical physics is actually philosophy." Born meant The new ideas in physics amount to a different view of reality. The world is not a fixed array of objects out there. It shifts under our gaze, interacts with us, and its knowledge has to be interpreted by us. Judgement must be used to do this.

Which waves are longest and provide the crudest image?

Radio waves, the low notes

What happened to the great German scientists?

Silence fell, many scientists left.

Why was string theory a backwater in physics?

String theory had nothing to do with nature and was not taken seriously.

What are strings?

Strings are made of tiny vibrating strands of energy.

How do strings produce different particles?

Strings are made of tiny vibrating strands of energy. It can vibrate and wiggles in different ways, which represents the different particles. Each "note" describes a different particle.

What do these new forces do?

Strong nuclear force - acts as a super glue, holding nucleus together, binding protons to neutrons Weak nuclear force - turns neutrons into protons, giving off radiation during the process

What new aspect of string theory is revealed when strings are shrunk in size?

The Graviton

What did Heisenberg say about the electron in 1927?

The electron is a particle which yields only limited information. If you want to fire it at a certain speed or direction, you cannot specify exactly what its starting or ending point is.

What is expected to happen if we go back even farther than in 12 above?

The electroweak force would unite with the strong force to become one grand super force.

What makes the elementary constants have the values that they do?

The extra dimensions cause one string to vibrate to produce a photon, another string vibrates producing an electron.

Why do we think string theory can unite gravity and quantum theory?

The graviton is a particle that transmits gravity at the quantum level.

How does the image of the face change as the wavelength of light used to observe it changes?

The image changes as the wavelength of light changes. The spectrum of red to violet light is only an octave of the range of invisible radiations.

Why do we say that the microscope enlarges the image but cannot improve it? What fixes the sharpness of the image?

The microscope enlarges the image but cannot improve it. The sharpness is fixed by the wavelength of the light. We need a shorter wavelength to see more detail. The use of ultraviolet light is shorter and can help us see this, but our eyes cannot detect it.

What happened to scholarship in Germany in 1935?

The nationalist socialist party came to power, scholarship was destroyed almost overnight.

What is the crucial paradox of nature?

The paradox of nature is that we cannot ever be certain. As we go to shorter and shorter wavelengths we expect to see more detail, but then the radiation starts penetrating so much we can only get shadows for images.

Why should we call Heisenberg's principle the tolerance principle?

The principle of uncertainty is a bad name. In science or outside of it, we are not uncertain. Our knowledge is merely confined within a certain tolerance. We should call it the principle of tolerance. Science as progressed step by step, the most successful enterprise in the ascent of man because it has understood that the exchange of information between man and nature and man and man can only take place with a certain tolerance.

What is Heisenberg's principle? What is the limit of knowledge?

The principle of uncertainty. No events not even atomic events can be described with certainty with zero tolerance. He specifies the tolerance that can be reached: Max Planck's quantum. Knowledge is limited by the tolerance.

Where does general relativity fit in the quantum world? What is the problem?

The quantum world tells how all of nature's forces work except for gravity. No one could figure out how to fit general relativity and the quantum world together.

What is space-time? How is this related to the speed of light?

The three dimensions of space and single dimension of time are bound together in a single fabric of space-time. These ripples of gravity travel at the speed of light.

What did Einstein think about the speed of light?

The velocity is a cosmic speed limit that nothing in the universe can exceed. Light doesn't travel instantaneously. It takes time for it to travel.

What has physics taught us about absolute knowledge?

There is no absolute knowledge, and those who claim it open the door to tragedy. All information is imperfect. We have to treat it with humility and that is what the human condition says and that is what quantum physics says.

What is the problem with string theory at present?

There is no way to prove strings exist. Experiments cannot prove or predict strings.

How are forces related to messenger particles?

These are sometime called field particles. Forces (such as gravity) are carried by these particles. The particles are exchanged between the two bodies and this exchange is what gives rise to Newton's third law. The graviton is the messenger for gravity, the photon for E/M. The W+, W- and Z for the weak.

What happens to the weak and electromagnetic forces when we go back in time until just after the big bang?

They would have been indistinguishable. They melt together and unite, become the electroweak force.

Why did Einstein want to unify the forces? What religious significance did this have for Einstein?

Unify gravity with electromagnetism to create a master equation that could describe the entire universe. Einstein wants to know the mind of God.

How could dimensions be invisible to us?

We need to be smaller to see them. The mathematics of string theory require six extra dimensions - only difference is their shape.

What is the role of the weak force in the universe? The strong force? The electromagnetic?

Weak force is responsible for radioactive decay. Strong force is the force that glues protons and neutrons together in an atom Electromagnetism produces light, electricity, and magnetic attraction

How did DeBroglie add the wave properties of electrons to the Bohr model?

When DeBroglie introduced the idea of electrons having a definite wavelength suddenly the quantum assumption made sense. The allowed orbits had standing waves much like string instruments.

Who won the first Nobel prize? What was the prize awarded for?

Wilhelm Conrad Röntgen in 1901 for inventing the x-ray.