Phileas Fogg Learns Physics - The Planck Constant - Not Just a Scale Factor (J-s)

What is the Planck constant (definitionally)?

The Planck constant is a physical constant, summarised thus: "A photon's energy is its frequency multiplied by the Planck constant"

This is summarised by the formula, E = hf.

The above is sometimes called the Planck-Einstein (or just the Planck) relation.  This is considered part of quantum mechanics.

Planck calculated the value of h from experimental data on black-body radiation.

What this helps us understand phenomena such as the photoelectric effect and black-body radiation.

How is frequency of a photon measured?

For low-frequency photons, you can directly measure the oscillation frequency of the EM field using electronic frequency counters.

What are the relevant units? (Hint: go from the known, to the unknown)

E is energy, measured in Joules.  

Frequency has units hertz, which means "per second" or "cycles (scalar, dimensionless quantity) per second". The Planck constant, therefore, by implication, must have the units J-s (Joule-seconds).

OK. So the Planck constant is not just a scaling factor on frequency - to level it up to the energy level of the photon - it is something more meaningful. 

Planck introduced it as a "quantum of action" - the smallest possible unit of physical action. Its dimension of energy x time represents action.

Curioser and Curioser Thought Alice

MIT OpenCourseWare has some dope online materials to learn some of the most interesting things in the known universe.  Here are some recommendations; tried and tested for total coolness..

The Early Universe, Professor Alan Guth (first lecture asks: Is Our Universe Part of a Multiverse?)

Physical Chemistry, Professor Robert Guy Griffin, Professor Troy van Voorhis (first lecture: Where does quantum physics fit into chemistry?)

Bio-Inspired Structures, Professor Leo Daniel (first lecture: observing birds leading to human flight, quite natural given Professor Daniel specialises in aeronautics).

Azimuthal Quantum Number

Azimuthal quantum number is a quantity that is being increasingly talked about in chemistry.  The concept comes from quantum mechanics, and is a number assigned to an atomic orbital - a function that describes the wave like behaviour of an electron in an atom. Certain classes of elements in the periodic table such as transition metals are classified by their azimuthal quantum number.

What is a dichroic material?

 A dichroic material causes visible light to be split up into different wavelengths, that manifest as colours.

Bill Gilbert on Magnetism (De Magnete)

William Gilbert was an English physicist and physician (for a few years he was the physician of Elizabeth I) and also a natural philosopher.  In 1600 he published a book on magnets called De Magnete. He was born in the historic English market town of Colchester in Essex and studied medicine at St John's College, Cambridge.  His experiments concluded that the Earth is magnetic and this was the reason compasses point North and he further argued that iron was at the centre of the Earth. Francis Bacon, philosopher and former Lord Chancellor, attacked Gilbert's conclusions on magnets arguing he had "built a ship out of a shell".

Didcot - The Railway Town with a Scientific String to its Bow

The town of Didcot, known for its railway heritage (the railway station opened as part of the Great Western Main Line in 1844), and 15 miles south of Oxford, is home to several scientific hubs for the UK.  

These include the Harwell Campus.  

The CCFE (Culham Centre for Fusion Energy) is also in the vicinity where the Joint European Torus (JET) is located. Culham's aim is to bring fusion energy to the grid. Fusion consists of fusing light nuclei to form heavier nuclei, at the same time releasing energy. The Culham approach is to heat a combination of hydrogen gases (deuterium and tritium) to very high temperatures (over 100 million degrees Celcius) to turn the gas into plasma. Nuclei combine to form a helium nucleus and a neutron, a small fraction of the mass is converted to energy. A ring-shaped magnetic chamber called a 'tokamak' is used to control the plasma. 

More details on science facility development in the UK can be found on the UKRI (UK Research and Innovation) dedicated site.

Legend of Lord Rayleigh - Co-Discoverer of Argon Known also for Clarity and Simplicity of Diction

Lord Rayleigh (John William Strutt) was a force in British physics and a President of the Royal Society.  He also won the Nobel Prize for Physics in 1904. 

Some of his great achievements include:

• Rayleigh Scattering - which can explain why the sky is blue
• Co-discovered argon gas (one of the so-called noble gases)
• Predicted the existence of Rayleigh waves (surface acoustic wave, which form part of seismic waves during earthquakes)

Rayleigh's intellectual background was distinctly mathematical (leading to initial research into optics and vibrating systems) and he was also known for his clarity and simplicity of diction. His eldest son became a professor of Physics at Imperial College.

Nautical Miles and Knots

A nautical mile is 1.852 kilometres. 

A regular mile is 1.6km. So a nautical mile is greater than a mile, by around 200m.

The knot is defined as one nautical mile per hour.

Gyroscope

A gyroscope is used for measuring and maintaining angular velocity.

Understanding the Physics behind RF Equipment - From kilo Hertz to giga Hertz

Airports employ a range of RF equipment such as ILS (instrument landing systems) or MLS (microwave landing systems).  The purpose of an ILS is to enable pilots to land without visual contact of the runway. It does this by transmitting radio signals.

The development of RF equipment came out of the study of "radio science".

RF refers to e-m wave frequencies between 3 kHz to 300 GHz (giga - ten to the power nine, or a factor of a billion). 300 GHz is a really really high frequency if you think about it.

Waves in the range of 30 GHz to 300 GHz are termed extremely high frequency (EHF) waves and were first investigated in the 1890s by Jagadish Chandra Bose.

What could such EHF waves possibly be used for?  In many former USSR nations, they are used in medical treatments (known as millimeter wave (MMW) therapy).

Hertz is the SI unit denoting one cycle per second. It is named after Heinrich Rudolf Hertz, the Hamburg-born German physicist who proved electromagnetic waves exist, a notion first theorised by the Scot, James Clerk Maxwell. At one time, electromagnetic waves were termed "Hertzian waves" by scientists.

"Energy of a Photon" by Maxwell Planck

Energy of a photon, E, is proportional to its frequency, v, E = hv. This is a basic law of physics and one very easy to forget if not used daily.

The constant h is known as the Planck's constant.  (f is the frequency of the corresponding e-m wave). It is also known as the Planck-Einstein relation. The constant's unit is Joule seconds (energy integrated over time).

Put another way, the Planck constant is the proportionality ratio between the energy and frequency (equivalent wave frequency) of a photon. Its natural units are therefore quite understandably Joule seconds.

Think "wave-particle duality" and you will have a vague sense of what Planck's constant imputes.

Nobel Prize in Physics 2016 Awarded for Topology Applied to Materials Science

The Winners

Half of the prize goes to David Thouless. The rest is shared between Duncan Haldane and Michael Kosterlitz.

A Common Academic Background

Thouless attended Trinity Hall, one of the oldest of the 31 colleges in the UK's Cambridge University, founded by the Bishop Bateman of Norwich in 1350.

Michael attended Gonville and Caius College in Cambridge (alumni are known as "Caians") and Duncan Haldane at Christ's College Cambridge, a relatively modern college having been founded in 1505.

What they are doing now

Duncan Haldane teaches Physics at Princeton University. All three are experts in condensed matter physics.

What is topology very roughly?

Topology is the study of spaces whose properties remain constant under continuous deformation like stretching and bending. It's useful mathematics because its linked to the physical world.

Keeping up to speed with the Physics world

Nature Physics is a publication that gives you updates on the latest research impacting Physics.

The Nobel Prize in Physics

To understand the impact of physics on the world, and the achievements of physicists in recent history, it is very important to have, at very least, a cursory awareness of the Nobel Prize of Physics over the years, and the winners who won them. It has been awarded since 1901, with the first winner being Wilhelm Roentgen, who discovered "Roentgen Rays" now better known as "X rays". He donated the monetary reward he received to his university. The 1902 prize was awarded to Lorentz and Zeeman for the discovery and theoretical explanation of the "Zeeman effect". Its practical use is in magnetograms showing the variations in the magnetic field of the sun.

When did the Dinosaurs Get Extinct?

The dinosaurs are believed to have gone extinct around 66 million years ago, as part of a mass extinction sometimes known as Cretaceous-Tertiary (or "K-T") extinction that wiped out as many as three quarters of plant and animal species on earth. Evidence for this extinction lies in iridium rich layer of sediment found in rocks believed to have come from an asteroid.

The asteroid theory has been dubbed the Alvarez hypothesis after the Nobel prize winner and San Francisco-born Luis Alvarez who proposed it. Luis Alvarez gained his PhD from the University of Chicago and was a member of California's Bohemian Club (founded 1872). Observing particle interactions through a bubble chamber he designed was key to him winning the Nobel Prize.

Solid State Physics - What is it?

Solid state physics is exactly what the name says, it's the study of the physics (physical properties) of solids and how they emanate from properties at the atomic level.

In other words, it is about how the micro impacts the macro.

Practically speaking, solid state physics is the theoretic basis of the very practical science of Materials. Materials science has led to the development, for example, of composite materials.

Many universities are pursuing research into solid state physics. Examples include Warwick University which has a research team focusing on ssNMR (solid state nuclear magnetic resonance).

Solid state physics aside, it is extraordinarily beneficial to understand physics in general to understand:

a) how the world works
b) understand the future of science

How do Solar Cells Work? (Think Photons and Electrons)

A photovoltaic system uses solar panels to supply usable electric power.

Solar panels make use of the PHOTOVOLTAIC effect whereby photons from the sun hit the semiconducting material and liberate electrons.

Carrier generation and recombination knowledge is needed to understand properly how solar cells work. This is part of solid state physics, the largest branch of condensed matter physics.

Note: the photovoltaic effect is closely related to the photoelectric effect, whereby electrons are emitted when light is shone on a material. According to the "classical electromagnetic theory" this is due to the transfer of energy from the light to an electron.

Photon Scattering

When photons are scattered from an atom or molecule (pit stop - what do mean by scattering - informally, the collision of a wave with a material object results in "scattering" of the wave) most photons are scattered such that they retain their "energy" (frequency and wavelength) which is known as Rayleigh or elastic scattering.  Raman scattering is inelastic scattering (whereby the photon is re-emitted from the medium with lower energy). It is the science behind the technique known as Raman spectroscopy and enabled Raman to win the 1930 Nobel Prize for Physics.

IIT Kharagpur - The First of the IITs

The first Indian Institute of Technology was IIT Kharagpur, founded in 1951, at which Nehru gave the first convocation address in 1956.

He called it "India's future in the making". It was declared an Institute of National Importance by the Indian Institute of Technology (Kharagpur) Act.

Kharagpur is in West Bengal, in the Eastern part of India (state capital Calcutta, or Kolkata).

The second IIT to be founded was IIT Bombay in 1958. Campuses were scattered throughout India to prevent regional imbalance.

Entrance to IITs is by Joint Entrance Exam (JEE). Exams must be taken in:

• Physics
• Chemistry
• Mathematics 

plus an additional aptitude test for Architecture candidates (where knowledge of famous monuments and their architects is tested).

In mathematics, some of the more tricky or unusual requirements include the following.

e.g. knowledge of harmonic series. In the harmonic series, each term is inverse of a term in an arithmetic progression. e.g. 1,2,3,4,5.. becomes 1, 1/2, 1/3, 1/4, 1/5.  Each term of the harmonic series is the harmonic mean of neighbouring terms (2(x1)(x2) / (x1+x2)).

Also analytic geometry skills must be extremely good. e.g. do you know the equation of a circle? For a circle with centre (a,b) the easiest way is to think of it in terms of its "standard form" (x-a)^2 + (y-b)^2 = r^2. The equation x^2 + y^2 = 1 is the unit circle centre (0,0).

In chemistry, some of the basic concepts you will need include kinetic theory of gases (the idea of gases as collections of atoms and molecules moving randomly in space).

Physical chemistry topics are required (where we apply physics to chemistry), covering how matter behaves at the molecular and atomic level, and explaining how reactions occur. John Dalton's premise that all matter is composed of atoms is assumed.