fuckyeahfluiddynamics:

Like many sports, the gameplay in football can be strongly affected by the ball’s spin. Corner kicks and free kicks can curve in non-intuitive ways, making the job of the goalie much harder. These seemingly impossible changes in trajectory are due to airflow around the spinning ball and what’s known as the Magnus effect. In the animation above, flow is moving from right to left around a football. As the ball starts spinning, the symmetry of the flow around the ball is broken. On top, the ball is spinning toward the incoming flow, and the green dye pulls away from the surface. This is flow separation and creates a high-pressure, low-velocity area along the top of the ball. In contrast, the bottom edge of the ball pulls dye along with it, keeping flow attached to the ball for longer and creating low pressure. Just as a wing has lift due to the pressure difference on either side of the wing, the pressure imbalance on the football creates a force acting from high-to-low pressure. In this case, that is a downward force relative to the ball’s rightward motion. In a freely moving football, this force would curve its trajectory to the side. (GIF credit: SkunkBear/NPR; original video: NASA Ames; via skunkbear)

fuckyeahfluiddynamics:

Like many sports, the gameplay in football can be strongly affected by the ball’s spin. Corner kicks and free kicks can curve in non-intuitive ways, making the job of the goalie much harder. These seemingly impossible changes in trajectory are due to airflow around the spinning ball and what’s known as the Magnus effect. In the animation above, flow is moving from right to left around a football. As the ball starts spinning, the symmetry of the flow around the ball is broken. On top, the ball is spinning toward the incoming flow, and the green dye pulls away from the surface. This is flow separation and creates a high-pressure, low-velocity area along the top of the ball. In contrast, the bottom edge of the ball pulls dye along with it, keeping flow attached to the ball for longer and creating low pressure. Just as a wing has lift due to the pressure difference on either side of the wing, the pressure imbalance on the football creates a force acting from high-to-low pressure. In this case, that is a downward force relative to the ball’s rightward motion. In a freely moving football, this force would curve its trajectory to the side. (GIF credit: SkunkBear/NPR; original video: NASA Ames; via skunkbear)

(via atomic-whale)

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jtotheizzoe:

Richard Feynman discusses why there is a difference between the past and the future, in this clip from his legendary 1964 lecture series at Cornell: The Character of Physical Law.

It’s well worth taking 45 minutes out of your day to hear Dr. F explain why the workings of nature unfold in one direction. You see, while we innately know that the future is different from the past, and so much of our conscious experience is built around the fundamental just-so-ness of time moving forward, the equations of physics describing phenomena from gravity to friction can be run in either direction without breaking the rules. Yet irreversibility is what we observe.

That’s where entropy and probability come into play. When we take into account complex systems, like the jiggles and wiggles of the uncountable atoms that make up our bodies and this chair and my coffee and our world and even out to the scale of the universe itself, there is simply a greater chance that things will become more disordered than less. It’s not that the universe can’t run in reverse, it’s just that there are so many other ways for it not to.

Or as Feynman says, nature is irreversible because of “the general accidents of life”.

This seven-part series, which Open Culture has assembled in its entirety, captures the physicist in his prime, one year before he won the Nobel Prize and became a household name. Feynman was seemingly born for the scientific stage. He had this uncanny ability to weave profound observations of the universe’s inner workings with off-the-cuff (and often brash) humor. James Gleick wrote of Feynman’s unique style and skill:

He had a mystique that came in part from sheer pragmatic brilliance–in any group of scientists he could create a dramatic impression by slashing his way through a difficult problem–and in part, too, from his personal style–rough-hewn, American, seemingly uncultivated.

This clip was a huge influence on my recent video Why Does Time Exist? Although my take scarcely measures up to Dr. Feynman, you can watch below:

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(Source: chandra.harvard.edu, via chris-tophe)

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(Source: runningonoatmeal, via physicsninja)

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(Source: studygeek, via physicsninja)

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Misconceptions About the Universe

The expanding universe is a complicated place. During inflation the universe expanded faster than light, but that’s something that actually happens all the time, it’s happening right now. This doesn’t violate Einstein’s theory of relativity since nothing is moving through space faster than light, it’s just that space itself is expanding such that far away objects are receding rapidly from each other. Common sense would dictate that objects moving away from us faster than light should be invisible, but they aren’t. This is because light can travel from regions of space which are superluminal relative to us into regions that are subluminal. So our observable universe is bigger than our Hubble sphere - it’s limited by the particle horizon, the distance light could travel to us since the beginning of time as we know it.”

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skeptv:

Over the Rainbow: How DOUBLE Rainbows Form

via scishow:

Take a look… A VERY special guest, LeVar Burton, explains how Double Rainbows are formed.

We’re super excited about this episode, y’all! Double rainbow power!

Support Reading Rainbow on Kickstarter

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(Source: a-night-in-wonderland, via tohoundnature)

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zerostatereflex:

Nice! Some guys are trying to fund this badass phenomenon of physics so we can all enjoy it. :D

"FLUX is based on a complex, thus rarely known law of physics, a phenomenon called Lenz’s law, which can defy our most commonly experienced physical law, gravity itself. It’s actually nothing new. Heinrich Lenz discovered it in the 1830s, we call it Lenz’s law to honor his discovery ever since."

"Every time the magnetic field changes inside a conducting material, it induces a voltage called electromotive force. Depending on the resistance of the material, it creates a current which behaves just like in traditional electromagnets: produces an additional magnetic field. Lenz’s law states that the magnetic field created by this induced current is so directed as to oppose the change in the source flux. To put it more simply, if you create a changing magnetic field by moving a magnet, it will produce a mechanical force trying to slow down the motion. The faster you move, the stronger the force gets. Every time."

Fund it here if you’re feeling this magical ish,..

FEEL FLUX.

(via thepoemthatdoesntrhyme)

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(Source: astrodidact, via bloodredorion)

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