Sciencemadness Discussion Board - Bike Centrifuge

Bike Centrifuge

Texium - 8-3-2014 at 12:36

Today I was preparing some copper carbonate from copper sulfate and sodium carbonate, and wanted to centrifuge the product to speed up the separation. Since I don't have a centrifuge, I turned my mountain bike upside down and used it as a makeshift centrifuge, securing the vial with duct tape. It worked surprisingly well! Here's some pictures, before and after.

jock88 - 8-3-2014 at 13:25

Classic!!!

subsecret - 8-3-2014 at 18:21

THAT'S INGENIOUS

Good idea. You could also use a ceiling fan if you have one, if you're feeling too lazy to spin the bike pedals. Be sure to add a counterweight to the opposing blade, if you've got an even number.

The_Davster - 8-3-2014 at 18:31

You can also duct tape some rope to what you need to centrifuge and swing it wildly in circles over your head.

Gearhead_Shem_Tov - 8-3-2014 at 19:11

Somewhere I've seen a centrifuge improvised from a blender motor. It was a permanent hack, if I remember right. But the bike centrifuge is indeed a classic.

I remember using one to g-test payloads meant for model rockets about forty years ago. To my shame and embarrassment, I must admit one of those payloads was a mouse. Fortunately, the test wasn't fatal, though the mouse was visibly dizzy for many minutes afterwards.

I'd purchased the mouse specifically for rocket experiments, but after seeing how affected it was from just thirty seconds exposure to a fairly low RPM, I ceased such "research".

I never did launch that (or any other) mouse in a rocket, and it went on to a reasonably long life after that. Somehow, though, I feel guiltier thinking about it now than I did when I was twelve. I can't even imagine my two teenage sons even contemplating doing such a thing today, and they would no doubt be horrified to hear the tale. Perhaps there really is progress.

-Bobby

TheChemiKid - 8-3-2014 at 21:05

If you find the blender hack, please share it.

Gearhead_Shem_Tov - 8-3-2014 at 21:47

Here's one approach to hacking a blender:

http://citsci.blogspot.com.au/2009/11/centrifuge-revisited.h...

I don't believe this is the one I remember because I think it was a bit more refined than this one.

-Bobby

Gearhead_Shem_Tov - 8-3-2014 at 22:11

Here's the one I remember:

http://jesseenterprises.net/amsci/1998/01/1998-01-body.html

TheChemiKid - 9-3-2014 at 05:10

Thanks!

Zyklon-A - 9-3-2014 at 09:15

I will try the blender centerfuge, I have two or three extra cheap blenders.

phlogiston - 9-3-2014 at 17:26

Gearhead_Shem_Tov, your experiments match remarkably well with the those done by Wernher von Braun pre-WOII when he was a student.

The following quote is from the book "Wernher von Braun" by Ray Spangenburg and Diane Kit Moser:

Quote:

In July through august 1931, Generales and von Braun had built a primitive centrifuge - a bicycle wheel, bolted horizontally to a table and rigged with a belt so it could be turned with a hand crank. To its perimeter, the two students attached containers to hold the white mice they used as test subjects. With the spinning bicycle wheel they could simulate, approximately, the accelerative force that anyone aboard a spacebound rocket would experience as it launched.
"We had no idea what the tolerance of the mice would be," Generales would later recount. "In the beginning, after a few turns of the wheel, the poort mice, whose hearts you could feel pounding in the palm of your hand, were placed on the table. We observed how the little creatures would scramble slowly at first and then faster in spiraling fashion..."

Quote:

Von Braun's Swiss land-lady, however, did not appreciate the spatters of mouse blood on her walls and threatened him with eviction if the experiments did not stop.