Welcome


The title says it all: this blog features physics videos found everywhere on the web: animations, demonstrations, lectures, documentaries.
Please go here if you want to suggest other nice physics videos, and here if I mistakingly infringed your copyrights. If you understand French, you'll find a huge selection of physics videos in French in my other blog Vidéos de Physique.

Saturday, 31 May 2014

Pulley Logic Gates

The essence of digital computing is the use of continuous physical states to represent a discrete number of symbols and the ability to perform logic based on those symbols. Although electronic circuits are exceptionally well-suited for this, any system that can handle symbols as both input and output is a digital computer.

Here, I've demonstrated the construction of simple digital computers (specifically, binary logic gates) using pulleys and weights.

Want to build your own? See the stuff you'll need here: bit.ly/pulleylogicgatesstuff
See pics here: bit.ly/pulleylogicgatespics
And feel free to reach out to me with questions: alex.gorischek@outlook.com

 
Pulley Logic Gates from Alex Gorischek on Vimeo.

Tuesday, 20 May 2014

Rube Goldberg Machine Winners

A Rube Goldberg machine is a machine that accomplishes a simple task in as complicated a way as possible. Every year Purdue University holds a Rube Goldberg Machine Contest. Teams of college students from all over the country design and build these machines and enter them in the competition. We invited this year's winners from Purdue University to show off their creation on the show.

 

Friday, 16 May 2014

NASA | Neutron Stars Rip Each Other Apart to Form Black Hole

This supercomputer simulation shows one of the most violent events in the universe: a pair of neutron stars colliding, merging and forming a black hole. A neutron star is the compressed core left behind when a star born with between eight and 30 times the sun's mass explodes as a supernova. Neutron stars pack about 1.5 times the mass of the sun — equivalent to about half a million Earths — into a ball just 12 miles (20 km) across.

As the simulation begins, we view an unequally matched pair of neutron stars weighing 1.4 and 1.7 solar masses. They are separated by only about 11 miles, slightly less distance than their own diameters. Redder colors show regions of progressively lower density.

As the stars spiral toward each other, intense tides begin to deform them, possibly cracking their crusts. Neutron stars possess incredible density, but their surfaces are comparatively thin, with densities about a million times greater than gold. Their interiors crush matter to a much greater degree densities rise by 100 million times in their centers. To begin to imagine such mind-boggling densities, consider that a cubic centimeter of neutron star matter outweighs Mount Everest.

By 7 milliseconds, tidal forces overwhelm and shatter the lesser star. Its superdense contents erupt into the system and curl a spiral arm of incredibly hot material. At 13 milliseconds, the more massive star has accumulated too much mass to support it against gravity and collapses, and a new black hole is born. The black hole's event horizon — its point of no return — is shown by the gray sphere. While most of the matter from both neutron stars will fall into the black hole, some of the less dense, faster moving matter manages to orbit around it, quickly forming a large and rapidly rotating torus. This torus extends for about 124 miles (200 km) and contains the equivalent of 1/5th the mass of our sun. The entire simulation covers only 20 milliseconds.

Scientists think neutron star mergers like this produce short gamma-ray bursts (GRBs). Short GRBs last less than two seconds yet unleash as much energy as all the stars in our galaxy produce over one year.

The rapidly fading afterglow of these explosions presents a challenge to astronomers. A key element in understanding GRBs is getting instruments on large ground-based telescopes to capture afterglows as soon as possible after the burst. The rapid notification and accurate positions provided by NASA's Swift mission creates a vibrant synergy with ground-based observatories that has led to dramatically improved understanding of GRBs, especially for short bursts.

 

How Do Rainbows Form?

SciShow explains how three important ingredients -- sunlight, water, and you -- interact to create the illusion of a rainbow. The colorful details are inside!

 

Wednesday, 14 May 2014

A virtual Universe

Scientists at MIT have traced 13 billion years of galaxy evolution, from shortly after the Big Bang to the present day. Their simulation, named Illustris, captures both the massive scale of the Universe and the intriguing variety of galaxies -- something previous modelers have struggled to do. It produces a Universe that looks remarkably similar to what we see through our telescopes, giving us greater confidence in our understanding of the Universe, from the laws of physics to our theories about galaxy formation.