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Wednesday, October 7, 2015

Nobel Prize in Physics 2015

The 2015 Nobel Prize in Physics was awarded to two physicists whose teams discovered a fundamental property of neutrinos. The work of Takaaki Kajita and Arthur B. McDonald showed that those tiny particles (with three types) change from one type to another.
from: symmetrymagazine

Saturday, October 3, 2015

Escape Velocity

In physics, escape velocity is the minimum speed needed for an object to "break free" from the gravitational attraction of a massive body. More particularly, escape velocity is the velocity (speed traveled away from the starting point) at which the sum of an object's kinetic energy and its gravitational potential energy is equal to zero. At escape velocity the object will move away forever from the massive body, without additional acceleration applied to the object. As the object moves away from the massive body, the object will continually slow and asymptotically approach zero speed as the object's distance approaches infinity.
For a spherically symmetric massive body such as a (non-rotating) star or planet, the escape velocity at a given distance is calculated by the formula
v_e = \sqrt{\frac{2GM}{r}},
where G is the universal gravitational constant (G = 6.67×10−11 m3 kg−1 s−2), M the mass of the body to be escaped, and r the distance from the center of mass of the mass M to the object. Notice that the relation is independent of the mass of the object escaping the mass body M. Conversely, a body that falls under the force of gravitational attraction of mass M from infinity, starting with zero velocity, will strike the mass with a velocity equal to its escape velocity.
In this equation atmospheric friction (air drag) is not taken into account.
Source: Wikipedia

In hyperPhysics website you can input some data and it gives the escape velocity:

See the escape velocity of Earth and Mars here:

full computaion here

Listen about escaping probes in this Astronomy Cast:

Saturday, September 19, 2015

Eratosthenes experiment

Source: wikipedia
On Wednesday, at local noon, each school in different countries will conduct the Eratosthenes experiment.

Eratosthenes  of  Cyrene (276 aC – 195/194 aC) was a Greek mathematician, geographer, poet, astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria. He invented the discipline of Geography, including the terminology used today. He is best known for being the first person to calculate the circumference of the Earth, which he did by applying a measuring system using stadia, a standard unit of measure during that time period. His calculation was remarkably accurate. He was also the first to calculate the tilt of the Earth's axis (again with remarkable accuracy).

To conduct the experiment and exchange data with other schools please go to this website:

You can also participate in the photo contest.

Be part of the Galileo Teacher Program (connecting teachers in all countries).

Scale Solar System

Sunday, August 16, 2015

Daily Physics News 08/16/2015

Posted from Diigo. The rest of my favorite links are here.

Monday, August 3, 2015

Daily Physics News 08/03/2015

Posted from Diigo. The rest of my favorite links are here.

Tuesday, July 21, 2015

Interactive Standard Model

Image credit: Simmetry Magazine

Symmetry Magazine post a great interactive information about the particles in the Standard model.
You can take a look here:

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