Wednesday, January 20, 2016

Physics in 2016

Scientific American has a useful look forward to 2016:
"The New Year may also be a year of discoveries for physicists plumbing the deepest mysteries of matter."

Wednesday, December 30, 2015

Albert Einstein - 70 years

Einstein is a scientist every science student should definitely know something about. He passed away 70 years ago this year.

According to an item in the Scientific American:
"Einstein is the most famous and beloved scientist of all time. We revere him not only as a scientific genius but also as a moral and even spiritual sage. Abraham Pais, Einstein's friend and biographer, called him "the divine man of the 20th century." 
To New York Times physics reporter Dennis Overbye, Einstein was an “icon" of "humanity in the face of the unknown.""

For more there is plenty at Wikipedia, of course, and here are two videos on Youtube:
How Einstein discovered E=Mc2
Albert Einstein documentary

Monday, November 30, 2015

New gamma-ray spectroscope

Some exotic physics in this device (developed at Vanderbilt and Fisk Universities) with some exciting space applications may get the interest of students.
"...a new generation of gamma-ray spectroscope that appears perfectly suited for detecting veins of gold, platinum, rare earths and other valuable material hidden within the asteroids, moons and other airless objects floating around the solar system" 
"The key to the new instrument is a recently discovered material, europium-doped strontium iodide. This is a transparent crystal that can act as an extremely efficient gamma-ray detector. It registers the passage of gamma rays by giving off flashes of light that can be detected and recorded."


Friday, October 30, 2015

Turbulence

A good example of a phenomena which seems simple but which gets very complex - water flowing through a pipe.
At low speeds the flow is smooth and predictable but at higher speeds turbulence makes things complicated. According to this report:
"A team of researchers from Austria, Germany and the U.K. has succeeded in building a model that shows the process that occurs when a liquid moves from a smooth state to one of turbulence inside of a pipe."
This is a good item to use to introduce in a general way the modelling of physical processes.

Tuesday, September 29, 2015

Challenging Concepts in Physics

Need help with difficult concepts? Advanced high school or starting university level? This MOOC at EdX should help. It is done by experienced teachers and includes:
 Acceleration
 Force Diagrams
 Momentum
 Rotational Motion
 Angular Momentum
 Standing Waves
 Conservation of Charge & Energy in Circuits
 Electrostatic Fields
 Gravitational and Electric Potentials
 Electromagnetic Induction
 Thermodynamics
 Pressure, Force & Flow in Fluids
 Diffraction & Interference
 Atomic Transitions

The course uses short instructional videos, on-screen simulations, interactive graphs, and practice problems.
Sounds really useful.

Monday, August 24, 2015

Reflections on a mug of tea

A question for students (its good to have an open ended question sometimes):

A ceramic mug of hot tea sits on a wooden table. Discuss how it cools. (Yes I know the picture does not show a wooden table... :) )

Convection from the surface is important.
Conduction through the sides and then cooling by convection significant too.
Cooling by radiation happens too although the temperature difference is small.
Conduction through the base not important as the ceramic is a poor conductor and the wood is worse.

How can the cooling be enhanced?
Convection is easily speeded up by a higher flow of air (blowing, fan, breezy location etc).
Putting a spoon in the cup increases conduction loss.
Using a black mug will help a little.
Drastic methods! (if you are late for work) - pour into another vessel, add ice etc.

Tuesday, August 11, 2015