Comments on: Supersonic ping-pong-ball gun leaves cartoonish ball-shaped hole in hapless paddles http://boingboing.net/2013/02/10/212100.html Brain candy for Happy Mutants Mon, 20 May 2013 09:15:00 +0000 hourly 1 http://wordpress.org/?v=3.4.1 By: Jeff Del Papa http://boingboing.net/2013/02/10/212100.html#comment-1653029 Jeff Del Papa Tue, 12 Feb 2013 07:20:00 +0000 http://boingboing.net/?p=212100#comment-1653029  The pumpkin gets sprayed with paint at weigh in.  (different color each day).  That would provided the equivalent of the wax.  I would do the experiment, but my vacuum pump is deeply buried.  The pumpkin gets sprayed with paint at weigh in.  (different color each day).  That would provided the equivalent of the wax.  I would do the experiment, but my vacuum pump is deeply buried.

]]> By: Scott McDaniel http://boingboing.net/2013/02/10/212100.html#comment-1652866 Scott McDaniel Tue, 12 Feb 2013 03:36:00 +0000 http://boingboing.net/?p=212100#comment-1652866 I've been thinking of two things, regarding this: 1)  Could you improve the range a bit by machining the nozzle to provide "rifling" to cause the air flow to spin? 2)  Supersonic Golf Ball Cannon... I’ve been thinking of two things, regarding this:
1)  Could you improve the range a bit by machining the nozzle to provide “rifling” to cause the air flow to spin?
2)  Supersonic Golf Ball Cannon…

]]> By: Scratcheee http://boingboing.net/2013/02/10/212100.html#comment-1652780 Scratcheee Tue, 12 Feb 2013 01:38:00 +0000 http://boingboing.net/?p=212100#comment-1652780 I noticed a complete lack of personal safety equipment in the soda can video.  No glasses, nothing. I noticed a complete lack of personal safety equipment in the soda can video.  No glasses, nothing.

]]> By: jimkirk http://boingboing.net/2013/02/10/212100.html#comment-1652592 jimkirk Mon, 11 Feb 2013 22:35:00 +0000 http://boingboing.net/?p=212100#comment-1652592 I'm not suggesting anyone try this ay home, but FYI, schedule 40 PVC 1 1/2  or 2 inch pipe operating pressure is greater than 11 atmospheres (198 psi for 1 1/2 inch, 166 psi for 2 inch).  Bursting pressure is about 5 times that.  But seals, joints and stuff tend to be weak points, so be careful...nudge, nudge, wink, wink. http://www.engineeringtoolbox.com/pvc-cpvc-pipes-pressures-d_796.html I’m not suggesting anyone try this ay home, but FYI, schedule 40 PVC 1 1/2  or 2 inch pipe operating pressure is greater than 11 atmospheres (198 psi for 1 1/2 inch, 166 psi for 2 inch).  Bursting pressure is about 5 times that.  But seals, joints and stuff tend to be weak points, so be careful…nudge, nudge, wink, wink.

http://www.engineeringtoolbox.com/pvc-cpvc-pipes-pressures-d_796.html

]]> By: Steve Tedder http://boingboing.net/2013/02/10/212100.html#comment-1652538 Steve Tedder Mon, 11 Feb 2013 21:53:00 +0000 http://boingboing.net/?p=212100#comment-1652538 The danger involved in building one of these things isn't what you might do with the ping-pong ball. The danger is the possibility that the pressure vessel might explode and injure someone. If you aren't completely confident of your ability to build such a vessel, you should leave this project alone. And remember, pressure vessels should be designed with a safety factor of at least five times the operating pressure! If you don't know how to do that, just say no! The danger involved in building one of these things isn’t what you might do with the ping-pong ball. The danger is the possibility that the pressure vessel might explode and injure someone. If you aren’t completely confident of your ability to build such a vessel, you should leave this project alone. And remember, pressure vessels should be designed with a safety factor of at least five times the operating pressure! If you don’t know how to do that, just say no!

]]> By: fuzzyfuzzyfungus http://boingboing.net/2013/02/10/212100.html#comment-1652531 fuzzyfuzzyfungus Mon, 11 Feb 2013 21:44:00 +0000 http://boingboing.net/?p=212100#comment-1652531 Having set a number on fire for, um, purely educational purposes, my experience has been that not-a-whole-lot of nitrocellulose, not enclosed in any sort of pressure vessel, flares up quite pleasingly but doesn't really 'detonate' in the sense that leaves you using base 8 when you count on your fingers... Having set a number on fire for, um, purely educational purposes, my experience has been that not-a-whole-lot of nitrocellulose, not enclosed in any sort of pressure vessel, flares up quite pleasingly but doesn’t really ‘detonate’ in the sense that leaves you using base 8 when you count on your fingers…

]]> By: Steve Langstroth http://boingboing.net/2013/02/10/212100.html#comment-1652471 Steve Langstroth Mon, 11 Feb 2013 20:45:00 +0000 http://boingboing.net/?p=212100#comment-1652471 I'll never make one. --- Pinky Swear! LOL!!! I’ll never make one. — Pinky Swear!

LOL!!!

]]> By: Gregg Grose http://boingboing.net/2013/02/10/212100.html#comment-1652277 Gregg Grose Mon, 11 Feb 2013 18:07:00 +0000 http://boingboing.net/?p=212100#comment-1652277 And the science gets done and you make a neat gun... And the science gets done and you make a neat gun…

]]> By: Jon Smith http://boingboing.net/2013/02/10/212100.html#comment-1652221 Jon Smith Mon, 11 Feb 2013 17:19:00 +0000 http://boingboing.net/?p=212100#comment-1652221 Great video, great presentation, but why would any professor from a science department at an accredited program even mention imperial measurements? Great video, great presentation, but why would any professor from a science department at an accredited program even mention imperial measurements?

]]> By: Jack Daniel http://boingboing.net/2013/02/10/212100.html#comment-1652182 Jack Daniel Mon, 11 Feb 2013 16:33:00 +0000 http://boingboing.net/?p=212100#comment-1652182 So when he says do not, DO NOT, try this at home, he actually means do...right? So when he says do not, DO NOT, try this at home, he actually means do…right?

]]> By: s2redux http://boingboing.net/2013/02/10/212100.html#comment-1652177 s2redux Mon, 11 Feb 2013 16:29:00 +0000 http://boingboing.net/?p=212100#comment-1652177 I expect that <i>experience</i> is commensurate with <i>8 college degrees</i> via the "yet another friggin' lab course" factor. I expect that experience is commensurate with 8 college degrees via the “yet another friggin’ lab course” factor.

]]> By: emo hex http://boingboing.net/2013/02/10/212100.html#comment-1652158 emo hex Mon, 11 Feb 2013 16:19:00 +0000 http://boingboing.net/?p=212100#comment-1652158 "Your love, like a supersonic pingpong ball, leaves a hole in my heart!" "thank you very much" “Your love,
like a supersonic pingpong ball,
leaves a hole
in my heart!”

“thank you very much”

]]> By: Marja Erwin http://boingboing.net/2013/02/10/212100.html#comment-1652098 Marja Erwin Mon, 11 Feb 2013 15:32:00 +0000 http://boingboing.net/?p=212100#comment-1652098 So you still need something to show the pressure itself doesn't. So you still need something to show the pressure itself doesn’t.

]]> By: NelC http://boingboing.net/2013/02/10/212100.html#comment-1652089 NelC Mon, 11 Feb 2013 15:21:00 +0000 http://boingboing.net/?p=212100#comment-1652089 <blockquote>Recommendation:  <i>do</i> weaponize.</blockquote> FTFY ;)

Recommendation:  do weaponize.

FTFY ;)

]]> By: James Craig http://boingboing.net/2013/02/10/212100.html#comment-1652087 James Craig Mon, 11 Feb 2013 15:20:00 +0000 http://boingboing.net/?p=212100#comment-1652087 I thought that warning was pretty ridiculous the first time I saw it and even more when repeated. They could have just said, "please don't try this at home; it is very dangerous" and left it at that.  I'm guessing that years of experience is more relevant than 8 college degrees in this instance. And, while it's great to have high-speed cameras and such, those do more to explain after the fact than to keep safe in the first place. Also, how'd they get those years of experience if they were following similar warnings? I thought that warning was pretty ridiculous the first time I saw it and even more when repeated. They could have just said, “please don’t try this at home; it is very dangerous” and left it at that. 

I’m guessing that years of experience is more relevant than 8 college degrees in this instance. And, while it’s great to have high-speed cameras and such, those do more to explain after the fact than to keep safe in the first place. Also, how’d they get those years of experience if they were following similar warnings?

]]> By: Jayarava http://boingboing.net/2013/02/10/212100.html#comment-1652071 Jayarava Mon, 11 Feb 2013 15:00:00 +0000 http://boingboing.net/?p=212100#comment-1652071 Yeah this was great. I like the warning about "don't try this at home we have college degrees and special equipment". If you look at their Youtube channel you can see them blasting soda cans http://youtu.be/VyCCo9i8Hwc and their special equipment for hearing protection consists of putting their fingers in their ears. No other safety equipment is visible, and one guys is standing about 1m away filming it on his phone.  Yeah this was great. I like the warning about “don’t try this at home we have college degrees and special equipment”. If you look at their Youtube channel you can see them blasting soda cans http://youtu.be/VyCCo9i8Hwc and their special equipment for hearing protection consists of putting their fingers in their ears. No other safety equipment is visible, and one guys is standing about 1m away filming it on his phone. 

]]> By: fuzzyfuzzyfungus http://boingboing.net/2013/02/10/212100.html#comment-1652049 fuzzyfuzzyfungus Mon, 11 Feb 2013 14:40:00 +0000 http://boingboing.net/?p=212100#comment-1652049 I know that a lot of produce carries the 'Coated with food-grade vegetable-, petroleum-, beeswax-, and/or shellac based wax or resin to maintain freshness.' tag and that that coating process is largely about reducing moisture permeability. Would such a mod disqualify a pumpkin?(It wouldn't save you from what happens to a gourd with 1 atmosphere of pressure inside and ~0 outside; but it could keep the amount of fluid bleed to a minimum over the relatively short pressurization interval allowed by the contest... I know that a lot of produce carries the ‘Coated with food-grade vegetable-, petroleum-, beeswax-, and/or shellac based wax or resin to maintain freshness.’ tag and that that coating process is largely about reducing moisture permeability. Would such a mod disqualify a pumpkin?(It wouldn’t save you from what happens to a gourd with 1 atmosphere of pressure inside and ~0 outside; but it could keep the amount of fluid bleed to a minimum over the relatively short pressurization interval allowed by the contest…

]]> By: SamSam http://boingboing.net/2013/02/10/212100.html#comment-1652015 SamSam Mon, 11 Feb 2013 14:05:00 +0000 http://boingboing.net/?p=212100#comment-1652015 Your math checks out. The energy of a 2.7g ping pong ball travelling at 900 mph is instead equivalent to that of a 3 kg (6.6 lb) turkey travelling at 27 mph. Regardless, I don't want to be on the receiving end of this turkey gun. Your math checks out.

The energy of a 2.7g ping pong ball travelling at 900 mph is instead equivalent to that of a 3 kg (6.6 lb) turkey travelling at 27 mph.

Regardless, I don’t want to be on the receiving end of this turkey gun.

]]> By: karl_jones http://boingboing.net/2013/02/10/212100.html#comment-1652007 karl_jones Mon, 11 Feb 2013 13:48:00 +0000 http://boingboing.net/?p=212100#comment-1652007 That's the way, uh-huh, uh-huh -- ! That’s the way, uh-huh, uh-huh — !

]]> By: karl_jones http://boingboing.net/2013/02/10/212100.html#comment-1652005 karl_jones Mon, 11 Feb 2013 13:46:00 +0000 http://boingboing.net/?p=212100#comment-1652005 Realist.  I want to be killed by the ping-pong ball <em>inside</em> the vacuum chamber.   Like in <em>2001: A Space Odyssey</em>, where David Bowman is making a suitless jump through hard vacuum, and HAL-9000 (deranged from singing "Bicycle Built for Two" too many times) fires a ping-pong ball into the open airlock. But seriously:  thank you for explaining the physics. Realist.  I want to be killed by the ping-pong ball inside the vacuum chamber.  

Like in 2001: A Space Odyssey, where David Bowman is making a suitless jump through hard vacuum, and HAL-9000 (deranged from singing “Bicycle Built for Two” too many times) fires a ping-pong ball into the open airlock.

But seriously:  thank you for explaining the physics.

]]> By: JonS http://boingboing.net/2013/02/10/212100.html#comment-1651911 JonS Mon, 11 Feb 2013 08:44:00 +0000 http://boingboing.net/?p=212100#comment-1651911  They'll probably have the ping pong ball gun having an effective range of, like, 800m. Instead of 8m. Because a massive contraption that can barely hurt you from across the room just isn't that scary, whereas a silent killer that leaves no traces and can getcha from three city blocks away ... oooooh, scary.  They’ll probably have the ping pong ball gun having an effective range of, like, 800m. Instead of 8m.

Because a massive contraption that can barely hurt you from across the room just isn’t that scary, whereas a silent killer that leaves no traces and can getcha from three city blocks away … oooooh, scary.

]]> By: Jeff Del Papa http://boingboing.net/2013/02/10/212100.html#comment-1651901 Jeff Del Papa Mon, 11 Feb 2013 06:57:00 +0000 http://boingboing.net/?p=212100#comment-1651901 Another deserving a little credit would be de Laval, who discovered the convergent/divergent nozzle shape. Another deserving a little credit would be de Laval, who discovered the convergent/divergent nozzle shape.

]]> By: Jeff Del Papa http://boingboing.net/2013/02/10/212100.html#comment-1651900 Jeff Del Papa Mon, 11 Feb 2013 06:54:00 +0000 http://boingboing.net/?p=212100#comment-1651900  It occurred to me to wonder what was going to happen to the pumpkin when it got exposed to vacuum.  There is a whole lot of water in the thing, that will be wanting to change state.  I suppose "best" case, you get some sublimation, and cooling.  You would get a lighter, and tougher gourd.  Worst case, you get a cracked mess, and/or DQ'd for modifying the gourd. (for those that haven't tried it, if you pull a vacuum on a container of water, the stuff first boils, then ice crystals form.)  It occurred to me to wonder what was going to happen to the pumpkin when it got exposed to vacuum.  There is a whole lot of water in the thing, that will be wanting to change state.  I suppose “best” case, you get some sublimation, and cooling.  You would get a lighter, and tougher gourd.  Worst case, you get a cracked mess, and/or DQ’d for modifying the gourd.

(for those that haven’t tried it, if you pull a vacuum on a container of water, the stuff first boils, then ice crystals form.)

]]> By: Pat R x 2 http://boingboing.net/2013/02/10/212100.html#comment-1651899 Pat R x 2 Mon, 11 Feb 2013 06:37:00 +0000 http://boingboing.net/?p=212100#comment-1651899 Hehehe! I saw this on the arXiv blog. They have a paper on it here: http://arxiv.org/abs/1301.5188 Hehehe! I saw this on the arXiv blog. They have a paper on it here: http://arxiv.org/abs/1301.5188

]]> By: Preston Sturges http://boingboing.net/2013/02/10/212100.html#comment-1651897 Preston Sturges Mon, 11 Feb 2013 06:22:00 +0000 http://boingboing.net/?p=212100#comment-1651897 If they use nitrocellulose ping pong balls, I would think the impact would make it detonate.  If not, they should work on it.  If they use nitrocellulose ping pong balls, I would think the impact would make it detonate.  If not, they should work on it. 

]]> By: tyger11 http://boingboing.net/2013/02/10/212100.html#comment-1651894 tyger11 Mon, 11 Feb 2013 06:01:00 +0000 http://boingboing.net/?p=212100#comment-1651894  I'd prefer they use ballistics gel with a high speed camera; that would be a lot more interesting to watch.  I’d prefer they use ballistics gel with a high speed camera; that would be a lot more interesting to watch.

]]> By: bzishi http://boingboing.net/2013/02/10/212100.html#comment-1651895 bzishi Mon, 11 Feb 2013 06:01:00 +0000 http://boingboing.net/?p=212100#comment-1651895 I think there is an error in your calculation. KE = 0.5 m*v^2 KE_1 = KE_2 m_1/m_2 = (v_2/v_1)^2 This gives a ratio of 225 for the mass. Apparently a ping pong ball has a mass of 2.7 grams, so the other mass would be 607.5 grams. This is way too small for a turkey, but it is close to that of a basketball at 60 mph. I think there is an error in your calculation.

KE = 0.5 m*v^2
KE_1 = KE_2
m_1/m_2 = (v_2/v_1)^2

This gives a ratio of 225 for the mass. Apparently a ping pong ball has a mass of 2.7 grams, so the other mass would be 607.5 grams. This is way too small for a turkey, but it is close to that of a basketball at 60 mph.

]]> By: ldobe http://boingboing.net/2013/02/10/212100.html#comment-1651891 ldobe Mon, 11 Feb 2013 05:35:00 +0000 http://boingboing.net/?p=212100#comment-1651891 Interesting proposition. I wonder if the vacuum might have a positive effect on keeping the pumpkin from going pie?  There might be less opposing force, since there's no air drag on the leading aspect of the gourd.....Although, the gourd would be slamming into a wall of air at the end of the tube.  If it's going mach 1.23, the heating might make it start to get all sloppy, or cause air pockets inside to expand some.  But then again, the pumpkin was already in a vacuum, which would make the air pockets expand as well. Fascinating.  I'm gonna have to go do some math now. Interesting proposition.

I wonder if the vacuum might have a positive effect on keeping the pumpkin from going pie?  There might be less opposing force, since there’s no air drag on the leading aspect of the gourd…..Although, the gourd would be slamming into a wall of air at the end of the tube.  If it’s going mach 1.23, the heating might make it start to get all sloppy, or cause air pockets inside to expand some.  But then again, the pumpkin was already in a vacuum, which would make the air pockets expand as well.

Fascinating.  I’m gonna have to go do some math now.

]]> By: Justin Sabe http://boingboing.net/2013/02/10/212100.html#comment-1651890 Justin Sabe Mon, 11 Feb 2013 05:33:00 +0000 http://boingboing.net/?p=212100#comment-1651890 I demand that Myth Busters shoot supersonic pingpong balls at pig cascaras or other human analogs now! So I don't have to. Because I don't need to spend tomorrow trying to find the best price for a pig locally and seeing if I end up on a FBI watch list for trying to source the parts from Home Depot... I demand that Myth Busters shoot supersonic pingpong balls at pig cascaras or other human analogs now! So I don’t have to. Because I don’t need to spend tomorrow trying to find the best price for a pig locally and seeing if I end up on a FBI watch list for trying to source the parts from Home Depot…

]]> By: Ian Anthony http://boingboing.net/2013/02/10/212100.html#comment-1651873 Ian Anthony Mon, 11 Feb 2013 04:47:00 +0000 http://boingboing.net/?p=212100#comment-1651873 Ah, but didn't it instantly generate a mental image that made you understand exactly what he was talking about? Ah, but didn’t it instantly generate a mental image that made you understand exactly what he was talking about?

]]>