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Among common household appliances, things one can make from stuff in the garage or hardware store, and reasonably safe, e.g. within reach of hobbyists and high school kids entering a science fair, what is the highest speed of motion of any bit of matter one can obtain?

The bit of matter, or surface points of some object, should be macroscopic - big enough to see, time the motion of somehow, make collisions with other bits of matter. Electrons aren't big enough! Fluids are fine too.

Guns, dynamite would be too dangerous. The tips of a fan blade or shutter edges in a camera are fine. Using a drill to make something spin real fast might be okay if all mad scientists involved are careful.

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closed as not constructive by Cedric H., nibot, mbq, Tobias Kienzler, Noldorin Nov 18 '10 at 15:18

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It depends what kind of object you want to be going that fast. Does it have to be a solid object? Does it have to be large enough to be visible? The electrons in a CRT television are moving at a sizeable fraction of the speed of light. –  Keenan Pepper Nov 17 '10 at 3:17
Could you give more detail on what your goal is, i.e. what you want to accomplish? Or is this simply curiosity? If you have a purpose in mind, giving more information will definitely help you. –  Mark C Nov 17 '10 at 3:18
No particular purpose, but I often ponder home-brew style experiments to illustrate one physics principle or another. Pushing the limits of what's possible, subject to everyday home or school boundary conditions. Having something move fast, or spin fast, comes up often. –  DarenW Nov 17 '10 at 3:40
Yes, large enough to be visible, though if there's an interesting idea requiring a microscope, let's hear it. Electrons or ions from an electric discharge wouldn't be interesting enough. –  DarenW Nov 17 '10 at 3:42
Try making an almost vacuum and shine a laser through it. Edit: I just realised you wanted matter. Connect an LED to battery and you have electricity! –  Dimensio1n0 Jun 28 '13 at 10:38

1 Answer 1

I'm going to assume that by "any bit of matter" you did not intend to include bits of matter of molecular or atomic size. For if you allow such small objects to be in the running then the higher velocity molecules in the air or in any steam you generate by heating water to boiling (the average of the squared speed is proportional to the absolute temperature) or in the glowing gas molecules comprising a candle flame would be moving at a good clip. But if we exclude such motions and just accept macroscopic or mesoscopic motions, then a reasonable candidate is the speed of the tip of an adroitly snapped rope or whip which exceeds the speed of sound when it produces the characteristic 'Crack!'.

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