These videos show why physics, the science of motion, is so captivating - be it motion in everyday life, in the universe, in machines or under the microscope.
The origin of the seasons
These animated satellite photographs show how the illumination of the Earth changes during the course of a year, from equinox to equinox:
A detailed explanation is found at https://apod.nasa.gov/apod/ap170319.html.
The simplest electric train
A pretty video on how to have fun with a coil, a battery and two magnets:
You do not need to buy an electric train for yourself or for your children any more.
The infinite belt trick
A wonderful and surprising video:
Did you know that a ball glued to an infinitely flexible sheet can be rotated continuously and for ever, if done properly?
Extreme slow motion: watch light bouncing off a mirror
At last, the videos we were all waiting for: Click here to watch how a light pulse moves through space, bounces off a mirror and enters a dense medium. (http://www.nature.com/articles/nature14005.epdf?referrer_access_token=5Z1oiOBInDp2O8g2WH-mUtRgN0jAjWel9jnR3ZoTv0NZ3EmFUOGYN0jLvU2WgUypCBLJdJFQiaxL30mA5vzOE6aU-cyBtfpDNKUwtqWklRawbNbIWqcwxODa1HC4ouM3)
Amplifying motion effects in everyday life
For a talk by Michael Rubinstein full of surprising effects, see this link to his TED presentation. He shows how to observe and visualize the heart beat through skin colour changes, how to detect sound through shape change of plastic bags or of plant leaves, and how to detect and visualize tiny motions of everyday bodies.
The Sun's surface and its fascinating motion
The chain fountain: the weird motion of a chain of beads
Steve Mould discovered the effect in 2013. See also the article at his site http://stevemould.com.
The motion and the growth of bacterial flagella
The fascinating motion of bacterial flagella, including the change of direction, is found on the page http://www.fbs.osaka-u.ac.jp/labs/namba/npn . Click here to download the mpeg file.
The incredible growth of bacterial flagella is also found on the page http://www.fbs.osaka-u.ac.jp/labs/namba/npn . Click here to download the mpeg file.
The diversity of bacterial motion
The fascinating motion of different types of bacteria can be watched on the film http://bio1151.nicerweb.com/med/Vid/Johnson4e/Wmv/Bacterial_Diversity.wmv.
Fun with mechanical motion
Accelerating and decelerating wheels helps moving across a surface, even if the wheels do not touch the surface at all.
How atoms switch orientation inside a magnet
This film, taken by Hendryk Richert at www.matesy.de shows how the magnetic regions in a material change when a magnet approaches. The film was simply made using a handheld magnet, a magneto-optic coating on a glass substrate and a usual video camera.
How geostationary satellites remain fixed even if the stars move
How stars orbit "our" black hole
Click here for a range of fascinating videos showing the motion, during ten years, of the stars around the huge black hole at the centre of our Galaxy. Without that black hole, the Milky Way and thus our Earth would not exist. The film was made with ESA telescopes.
The belt trick as proof of the spin-statistics theorem - first video. Spin 1/2 particles are fermions because belts with buckles have spin 1/2: indeed, two full rotations - but not a single one - are equivalent to no rotation at all. This is the defining property of spin 1/2.
This beautiful animation is copyright and courtesy of Antonio Martos. Assume that the belt cannot be observed, but the square belt buckle can, and that it represents a particle. The animation then shows that such a particle (the square buckle) can return to the starting position after rotation by 4 pi (and not after 2 pi). Such a `belted' particle thus fulfills the defining property of a spin 1/2 particle: rotating it by 4 pi is equivalent to no rotation at all. (The belt thus represents the spinor wave function; for example, a 2 pi rotation leads to a twist; this means a change of the sign of the wave function. A 4 pi rotation has no influence on the wave function.) You can repeat the trick at home, with a paper strip. The equivalence is shown here with two belts attached to the buckle, but the trick works with any positive number of belts! Can you find a proof for this? By the way, such belted buckles - together with equivalent constructs made of ropes or tubes - are the only possible systems that show the spin 1/2 property.
The belt trick as proof of the spin-statistics theorem - second video. Spin 1/2 particles are fermions, because belts with buckles behave like fermions: a double exchange - but not a single one - of particle position is equivalent to no exchange at all. This is the defining property of fermions.
This unique animation is copyright and courtesy of Antonio Martos. Assume that the belts cannot be observed, but the square buckles can, and that they represent particles. The animation shows that two particles (the two square buckles) that are connected to infinity by belts return to the original situation if they are switched in position twice (but not once). Such particles thus fulfill the defining property of fermions. (For the opposite case, that of bosons, a simple exchange would already lead to the identical situation.) You can repeat the trick at home, using paper strips. The trick is shown here with two belts per particle, but the untangling works with any number of belts! Together, the two animations are the essential parts of the proof that spin 1/2 particles are fermions. This result is called the spin-statistics theorem.
Flying around the Earth is worth it
The film shows the beauty of our planet. More details can be found here.
How atoms move
This film shows the motion of a number of atoms, and the way they change position. More details here.
The flickering of stars at night
The wave properties of matter
Click here to see quantum physics in action: a visualisation of the double split experiment for matter. This might be the best way to understand quantum theory.
More videos are found inside the free textbook
The pdf files of the Motion Mountain textbook also feature embedded films of moving electrons made visible in liquid helium, of the astonishing solitons in water, of the elementary particles inside atoms, about the motion of cilia that determine that our heart grows on the left side of our body, the world seen from a relativistic car, and much more. Just download the pdf files to see these videos; they all run inside Adobe Reader.
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