When Spun Really Fast, CDs Explode

Anonymous Coward writes: "Ever wonder why cd-rom/cd-rw drives are not getting any faster? Wonder why they heat up? This page has a rather amusing experiment where they put various CD's into something that can spin up to 30,000RPM and found that most cd's explode at just around 28,000RPM. Oh and they seem to like using Corel CD-ROM discs for their experiment." Update: Yep, it's a dupe...

Comments

better way

[xero_sign]

I prefer to just microwave mine..

Pah!

[popeydotcom]

They should at least have chosen AOL CDs to destroy. Sheesh.

Al.

Exploding CDs?

[kitzilla]

A lot of bands might consider exploding CDs a feature. :-)

Ooh, new copy protection idea...

[silverhalide]

I can see it now, the RIAA manufacturing discs that experience structural failure when you spin them faster than 1X to rip them....

oh boy.

Wonder what happens if you spin a floppy at 30,000 rpm? :-)

More Explosions!

[Inexile2002]

I want to see more of this kind of story!

I want to see what else can explode in my box. I want to see what happens (with big color pictures) to to a hard drive at 20000 atmospheres of pressure. I want to see ASUS vs ABit mobo's head to head for resisting g-forces. I want to see what happens when you force 100,000 volts through a cat-5 cable.

Isn't this what the internet is all about, pictures of stuff exploding, videos of people endangering their lives for my tittlation while discovering what happens if you fill a case with gasoline and run it as a server. Get cracking people.

Re:More Explosions!

[kwishot]

What happens when guys in IT departments get bored or "fed up" with hardware? Try hooking up common computer cables and connectors to 110vac for the purpose of destruction =) I especially like VGA killer and the "powered" hub!
Check it out at http://www.fiftythree.org/etherkiller/ (I've actually had the honor of seeing these things up close, and they're every bit as cool as you'd think! =)

Re:More Explosions!

[TheConfusedOne]

Well, I can't give you 20,000 atmospheres, but I can give you a tank driving over a hard drive.

http://homepage.cc/harddisk/

Enjoy. Personally, I think it would be more fun if they used the main gun to "partition" the disk.

Re:More Explosions!

[Lumpy]

I want to see what happens when you force 100,000 volts through a cat-5 cable.

i cant tell you about 100,00 voles but I can tell you about what happens when you shove 2-4 million volts down a cat-3 cable that is 400 foot in length.

I ran a cat-3 cable from my parent home to their deck in lake michigan for a telephone extension. I had aquired for them an old police call box, modified it to have the ability to be locked with a combination. (Jerks walking the Lake Michigan shoreline will happily make long distance or 1-900-nasty-sex calls on your phone for you if you dont.) so I ran some cheapo regular cat-3 wire out there for the 2 phone lines they have at the house and mounted a cheapo 2 line phone in the call box. (later changed it to a 2.4Ghz Cordless with custome antennas out the top... that's another story)

WEll we had a lightning storm. and silly/stupid me didn't think of these things and GROUND things at the phone box end on the beach. so we had a direct hit to the tree next to the phone box... It did the following.. The cat 3 cable was completely vaporized for 20 feet. It was gone, nothing NADA, as if aliens came and beamed it to their mothership with charring effects. the rest of the cable length had interesting things done to it.. From the charred point to the house where the first ground point was available (outside) it was broken every 1 foot, the every 2 foot and os on until it was up to every 10 feet had a section broken/burned out.. on close look you could see exit wound pinholes near the break point as the voltage found a weak point and escaped. My only explination was that the voltage continued to drop as it made it's way toward the good ground (or the rest of the house) and this was what was causing the increase in distance between breaks/burnout points.

Oh yeah, of the wires in the cat 3 cable... 4 were phone, 3 were alarm indicator from the house,1 for house is alarming, 1 for reporting to the house that someone opened the phone box wrong, and one was grounded at the house.

The alarm was blown up.. completely it was dead, circuit board fried, I stuck a fork in it and handed it to the insurance man.

3 of the 5 phones in the house were dead (electronic or cordless) the 2 old mechanical bell phones worked.

Re:Duplicate

[Tablizer]

This story (with the same URL) was [already] posted here [slashdot.org].

Slashdot staff has appearently been spinning in their chairs so fast that their memories centrifigully left their container.

Bannage target?

[Tablizer]

Oh great. Now CD players will be banned from planes.

Maximum Velocity? (Not Spin)

[Skevin]

I'm in the process of converting a WGP Autococker into a CD/DVD Launcher - specially flattened barrel, tightened on one side to impart a spin - to launch Compact Disks with a burst of CO2. Although the CD's needed to be loaded by hand, one at a time (up until recently), I can reliably attain ~550 ft/s. This is enough to cleave thick pieces of styrofoam/cardboard or aluminum cans in half... or embed itself into soft wood like Eucalyptus trees. Against harder targets, such as rocks, the rounds simply undergo fragmentation and splinter into tiny plastic chunks. I don't know the effects against animal matter yet, because the contraption is notoriously inaccurate and squirrels are annoyingly fast.
At higher velocities (~700 ft/s) the rounds begin to fragment in the "barrel". I'm currently examining other alternatives to increase the velocity, but I guess now I have to take spin to account. :)

Other notes: I've put together a rudimentary feeder/hopper that now lets me use my CD Launcher in a semiautomatic fashion (and wastes more CO2 per shot)

Solomon

PS: I'm slapping together a solenoid-actuated electric trigger frame (similar to a Sandridge) to convert my paintball^H^H^H^H^H^H^H^H^H CD gun to a fully automatic weapon. I don't know if it will work... yet. (I have given thought to converting an Angel, but I'm not willing to futz with $1300 gun, and I've been doing my own custom internals on 'Cockers for years now.)
I estimate a potential ROF of ~13 CDs/second. (maybe *now* I'll be able to hit that pesky squirrel) My anticipation is that it still won't do any damage to brick walls, bronze statues, and masonry of quality craftsmanship, but will absolutely *shred* old wooden fences, thrown-out sofas, and squirrels.
BTW, I once thought of calling it my Assault Ordnance Launcher, or AOL for short... the idea being that people would soon become afraid of my AOL CDs...

Re:Spin laser instead?

[Myco]

Actually, it's a little-known fact that all CD-ROMs do keep the CD stationary, and simply spin the rest of the universe around it. True fact. ;)

aol.yoyo.com

[Tablizer]

There goes my plans to turn all those free AOL disks into yoyo's to sell on ebay.

merry-go-round

[charlie763]

At what angular velocity would a child (~30kg) explod on a merry-go-round? What would happen if they were to have a CD in their pocket?

Re:Spin laser instead?

[cybermage]

Actually, it's a little-known fact that all CD-ROMs do keep the CD stationary, and simply spin the rest of the universe around it. True fact. ;)

Yeah, right. Next you're gonna tell me that CDs are flat and if you read too far you'll fall off the edge.

A faster way (2,466X)

[carambola5]

I take no credit for this, but I remembered reading an interesting comment on the last time slashdot posted something like this. All credit should go to labradore:

This is a good way to get a fast CDROM drive:

1. Buy a 10,000x10,000 dpi scanner with firewire interfeace
2. Write cdrom image analysis algorithm.
3. Scan cdrom image into temp hard drive space and analyse, extracting data

This is based on these rough figures:

• A cdrom is approximately ( PI*5^2 - PI*0.75^2 )= 76.75 sq. inches of data surface
• If a cdrom has about 5.6 billion bits on that surface then the density is roughly 76 million bits per square inch.
• That works out to about 8,800 bits per linear inch. Assume you will need a little better resolution than that because there is some empty space between the dots on a cd surface. 10,000dpi aught(sic) to be good enough.

Assuming that the scanner is faster than the firewire (400Mbps) and 10% overhead for the data transfer, each cd image will be approx. 7.3 billion bits, taking just over 20 seconds to transfer. This device is a 2,466x speed CDROM "drive". Put that in your Pentium and smoke it! Scanner and algorithm design left as an excercise for the reader.

Re:Spin laser instead?

[shepd]

Don't forget that CDs spin backwards in Australia.

Cheap and geeky way to overclock dremel tools

[dattaway]

Dremels can spin much faster than 30,000rpm. Those motors have a field winding and an armature winding. If you decrease the field current, it causes the armature current to go through the roof. This is called "field weakening" and is a common method to get motors to spin faster. The motor's speed can be expressed as a ratio of armature/field current. The motor's speed is that ratio.

AC motors are tricky to do that with, but one sure way to overclock a dremel motor is by "overclocking" one of those 120VAC inverters. Look for an opamp that generates the clock frequency and the resistor for that RC circuit can be replaced with a potentiometer. You can vary the frequency from 0 to about 400Hz. Higher the frequency, the higher AC motors will sync. Don't go to high on the frequency or the inverter's mosfets will exceed their slew rate. That means most of the energy they are trying to switch will be disapated inside themselves, because they can only switch between the voltage rails so fast. Another resistor on the opamps will adjust the voltage for charging the storage capacitor. This one will have the greatest effect. You can get most inverters to pump out over 200 volts. Use an oscilloscope to track down the inverter's signal generator.

I found a non-overclocked dremel will easily cause the cd's outer tracks to skew. Extreme vibration will be the result as the cd warps quickly. Speed will drop quickly due to this imbalance. Solution: turn up the power!

If Intel made CD-ROM drives...

[guttentag]

If Intel made CD-ROM drives, we would start seeing the following in 95% of new PCs:

1. A giant fan aimed at a heat sink attached to the spindle that grips the CD
2. Pressurized CD-ROM drives
3. A sticker on the "5x-the-speed-of-sound" drive stating that by using this CD-ROM drive, you agree that the speed of sound is one-tenth the speed the rest of the world claims.

One of the above would be appended to what we know today as a 24x CD-ROM drive.

Re:It depends on the age of the CD...

[MooseGuy529]

Anyone have info on changes in manufacturing od CD's over the years that might explain this?

Well of course, the newer it is the crappier LOL... like in the Simpsons episode where Bart meets Buck McCoy:

Bart: "What's this lunch box made of?" ::tap tap tap::

Buck: "Oh, back in our day, we had a thing called metal!"

Bart: "Me-tal... hmmmm..."