PowerLabs High Speed CD-Rom Experiments
Help me figure out new and more entertaining ways to blow up CDs!
Have you ever loaded a faulty CD into a high speed
(30X or higher) CD-ROM player, heard it spin up to incredible speeds,
rattling and whining, and thought to yourself: "this thing is going
to explode"? When CDs came out they were heralded as the solution for the
need for high storage-high speed information devices, transferring data at
a whopping 150kb/s, but like all technologies, 1x CD players quickly
became obsolete as the need for higher and higher transfer rates pushed
for faster players, and, with them, higher rotational speeds. As we
advance into the 21st century CD players are reaching the ultimate speed
limit: we are getting to the point where the CD player simply can not spin
the CD any faster or else the CD will literally fly apart.
On the interests of the advancement of high speed computing PowerLabs brings to you:
"THE ULTIMATE CD SPEED LIMIT!"
WARNING: This page is written for amusement only: These experiments are VERY hazardous!; A high speed rotating CD Rom is a bomb ready to explode and will send razor sharp plastic shrapnel in all directions when least expected. Do not attempt to replicate any of the experiments described below!
Before an experiment could be
devised where a CD would be rotated to complete failure, a proper motor had
to be obtained that would be capable of achieving those high rotational
velocities with the load presented by a CD. Although a CD is very light and
aerodynamic, when it starts to spin at a couple tens of thousandths of
rotations per minute the drag created by air around its surface can be
sufficient to slow the motor down considerably. High torque motors are very
common and cheap, as are small high speed motors. Unfortunately however,
high speed, high torque motors are a much rarer and expensive find.
At 35000RPM very small
imperfections and balancing errors can lead to extreme vibration; so much,
in fact, that it would be possible to damage the bearings or bend the axle
on the tool if something as heavy as a CD was to start wobbling (bear in
mind that the Dremel tool was designed for very small, light weight loads
and even then many of its attachments carry warnings not to be used at full
speed). One of the first challenges of the research was to find a means to
secure the CD perfectly in the middle of the tool. A custom made CNC lathe
spun aluminum holder was considered but before I ever left the room I
realized that the cylindrical sanding attachments Dremel makes not only fit
a CD hole perfectly, but also have adjustable width so that the CD could be
gripped in place.
The Dremel was switched on and the
rotational velocity was gradually increased to its maximum, at which point
the CD hummed and whined in a very menacing manner. Mildly disappointed that
it had not exploded, I realized that it wanted out; a quick jerk at
the tool and the CD slid out of the holder and contacted the carpet whilst
spinning at ungodly speeds. It peeled out a bit in front of me and proceeded
to make its way to the door at a very high speed. On contacting the closed
door, the CD did a most unexpected thing: it first bounced back a few
inches, and then, when it hit the door again, it jumped straight up the door
and struck the ceiling, exploding into thousands of fragments which rained
down on the entire room. This first experiment was unfortunately not
videoed, but it served to get everyone in the room to put glasses on and
cower away behind pieces of furniture, whilst people in the hall corridor
quickly made their way to my door to ask what was going on. Now, with an
audience, the camera was taken out and the real experimentation began...
At those speeds the CD is storing over 150joules of energy.
Conversely, if the CD was to explode at that velocity, the pieces would escape at a similar speed. Although a Dremel tool does not have the required power to sustain its maximum RPM with a load as big as a CD-Rom, the CDs did go very fast; fast enough to blow all the foil off from one of them, explode another, and launch several across the room at speeds high enough that they exploded on impact, or flew up to the ceiling. Videos are available below for your amusement.
Results and Discussion:
Click picture to watch the full CD experiment video (1m28, 8mb), or check
out the best exploding CD here. (6s
You'd think a CD could handle 52x, right? After all, they make drives
that fast.... but apparently that's not in the Playstation black-disc spec.
I tried playing GranTurismo on ePSXe, and it exploded right in the drive!
Comments? Mail me.
Hits since 06/06/2003.
Last updated 11/02/10
Help me figure out new and entertaining ways to blow up CDs!
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