Pi day (3.14) is Albert Einstein's Birthday! To celebrate, we'll explain 4 of his most groundbreaking papers from 1905, when he was just 26 years old. minutephysics is now on Google+ - http://bit.ly/qzEwc6 And facebook - http://facebook.com/minutephysics And twitter - @minutephysics Minute Physics provides an energetic and entertaining view of old and new problems in physics -- all in a minute! Music by Nathaniel Schroeder NEW ALBUM!! -- http://juliansaporiti.bandcamp.com/album/lusitania ... https://www.youtube.com/watch?v=hSgIDgGpRpk

Go to http://brilliant.org/MinutePhysics for 20% off a premium subscription to Brilliant! Mark Rober's youtube channel: https://www.youtube.com/markrober This video is chapter 7 in my series on special relativity, and it covers the idea that some things AREN'T relative: there IS a sense of absolute length and absolute time, which can be agreed upon from all moving perspectives (as long as they're inertial reference frames). In particular, proper length and proper time, aka the spacetime interval. Essentially, this is the spacetime version of the pythagorean theorem, and we'll explore it using the Lorentz transformations of lengths and time intervals, enacted with a mechanical minkowski diagram, aka mechanical Lorentz transformation, aka spacetime globe. Support MinutePhysics on Patreon! http://www.patreon.com/minutephysics Link to Patreon Supporters: http://www.minutephysics.com/supporters/ MinutePhysics is on twitter - @minutephysics ... https://www.youtube.com/watch?v=WFAEHKAR5hU

Hi! My name is Henry, I make MinutePhysics, and you can support me on Patreon: http://www.patreon.com/minutephysics Is it better to walk or run when it's cold out? If you run, then you have to deal with wind, wind chill, etc, but your body generates more heat. If you stay still, standing or walking slowly, you don't generate as much heat, but don't deal with the wind. Note: the simple calculations in this video don't very well take into account the baseline metabolic rate/heat generation, even at rest, of humans. REFERENCES Physics of Running Presentation: http://uw.physics.wisc.edu/\~reardon/Physics%20of%20Running.pdf Original Wind Chill Index formula: https://www.amazon.com/Factors-Design-Handbook-Wesley-Woodson/dp/0070717680 “The Basis of Wind Chill” paper: http://pubs.aina.ucalgary.ca/arctic/Arctic48-4-372.pdf ... https://www.youtube.com/watch?v=Re5fhBoF6sY

If gravity is so attractive, why doesn't the earth just crash into the sun? Or the moon into the earth? The answer: Stable Orbits hyperbolic funnel video: http://bit.ly/r5xhng minutephysics is now on Google+ - http://bit.ly/qzEwc6 And facebook - http://facebook.com/minutephysics And twitter - @minutephysics ... https://www.youtube.com/watch?v=uhS8K4gFu4s