8 ms·

I put a little salt water in a 3 liter bottle (remember those... Shasta, baby) and melted 2 wires through the cap. I connected those to a 12 volt battery and le

I put a little salt water in a 3 liter bottle (remember those... Shasta, baby) and melted 2 wires through the cap. I connected those to a 12 volt battery and let that cook until it was good and bulging, flipped it over and then used the firing coil from a motocycle to make a spark between the wires. It made a much bigger boom than we had expected. I believe the hole in the ground it left was nearly 2 feet deep. I think I was 13.

ISL 14y ago
Elegant. Particularly for thirteen.
jules 14y ago
I'm calling bullshit. I did that many times and never blew any significant hole in the ground (though because of impatience I started using 220V -- not a great idea). Yes it makes a loud boom, but a 2 foot hole no way.
- hluska 14y ago
  The joy of being 12/13 is that you're still in that cusp between child and semi-adult. You've got enough motor skills and knowledge to be dangerous, but still have the childlike sense of awe that can make things look significantly larger than they are!
  - masklinn 14y ago
    > still have the childlike sense of awe that can make things look significantly larger than they are! Considering some of the fishermen[0] I know, that one never goes away. [0] and guys I subsequently shared a locker room with
- aarongolliver 14y ago
  I agree. Though only if he used a plastic bottle. My father and I did this when I was in middle school. He (stupidly) held it in his hand. All it did was make a very loud boom, and not a two foot hole in his arm.
- noonespecial 14y ago
  1) Your 220 made mostly steam and little browns gas. 2) We had partially buried the bottle before setting it off.
  - jules 14y ago
    Certainly, that experiment didn't last more than a tenth of a second. Lighting a 3L bottle produces about 20kJ if my calculation is correct, so if you bury the bottle in sand or other loose soil I can see how it can move that, but well then most of the hole is because you dug it. If you have a bottle full you can safely light that with the cap off while holding the bottle in your hand, though I wouldn't advise doing the same with the cap on (you certainly won't lose your hand or anything, but it may be painful). For the people wondering, here is a video: http://www.youtube.com/watch?v=HmcaC0vxaSo http://www.youtube.com/watch?v=HmcaC0vxaSo
    - noonespecial 14y ago
      Interesting. Considering we never took the cap off and lit it off with the spark, wouldn't the amount of energy in the bottle go up with the pressure? Some people were saying here that a 3 liter might take as much as 250psi. We waited until the bottle was visibly distended. How would the calculation vary with pressure? I'd be interested to know the best(worst?) case scenario!
      - geon 14y ago
        > Considering we never took the cap off and lit it off with the spark, wouldn't the amount of energy in the bottle go up with the pressure? I have been playing a bit with a potato/hairspray cannon. If you don't have a good seal (that's why you use a potato), you get no boom. I tried to shoot snow, but it would just go hsssst. I'm thinking the initial combustion raises the pressure enough for the fuel mixture to detonate, and if the seal is't good enough, the fuel will just burn gradually.
      - jules 14y ago
        The calculation is already best/worst case. I simply calculated the enthalpy of 3 liters of the mixture. The energy due to the pressure buildup is negligible. If you didn't make sure that there is no air in the bottle, then the energy would in fact be considerably lower simply because then the bottle is mostly air (the way to make sure is by submerging and filling the bottle with water and wait until the bottle is completely filled with gas, and then closing the cap under water). BTW, speaking of pressure it's unfortunate that these days the soda bottles are so thin & weak, some can't even stand 5 bar anymore, they used to be a lot thicker and stronger.
jlgreco 14y ago
> 3 liter bottle (remember those... Shasta, baby) Sometimes store-brand colas will still have 3-liter bottles. They are pretty good for bicycle-pump/bottle rockets, if anyone is interested in that sort of thing.
- lotharbot 14y ago
  Make sure the mouth of the bottle is the proper size for your pump assembly. Sometimes 3L bottles have extra wide mouths.
gavinlynch 14y ago
Right. But you didn't do it during school. edit: Do I really need to point out that 2 felonies for this is obviously a gross overreaction by authorities and I hope all charges are dropped? That said, if you don't agree that it was universally horrible judgement to make a drano bomb during school, then there really isn't much to discuss between us and you can carry on downvoting (although I hope none of you are in charge of my future children). my longform response: https://news.ycombinator.com/item?id=5651593 https://news.ycombinator.com/item?id=5651593
- marssaxman 14y ago
  Oh, come on, having horrible judgement is the whole point of being a kid. The process of growing up and becoming an adult is all about learning and acquiring good judgement. How can you expect people to gain the judgement that comes with experience without allowing them to gain that experience by trying things, some of which will turn out to be mistakes? How are they supposed to know which things are going to be the mistakes without trying some of them and thereby learning the patterns? I once did more or less the same thing as Ms Wilmot did, and you bet I did it during school, and I didn't even bother to tell anyone about my intentions first! I set up an apparatus under one of the fume hoods in the back of the chemistry lab, dissolved a bunch of aluminum, captured the hydrogen in a balloon, and then blew the whole thing up. It made a hell of a big bang, shattered a bunch of glassware, and startled the hell out of my lab-mates. Bad judgement? Well, yeah. Duh. But I didn't actually hurt anyone, and I sure learned something from the experience, and I'll bet that all my classmates learned something from it too, without having to deal with the embarrassment and clean-up that landed on my shoulders for being the nitwit who tried it. Just imagine how fucked I'd have been if I'd had to face felony charges after that. My whole life might have been different, my whole software engineering career derailed before it had even started. What a stupid waste that would have been. What a stupid waste it is going to be for all of us if this idiotic treatment of Ms Wilmot is allowed to stand.
  - gavinlynch 14y ago
    Did you read my post? I do not agree with these felony charges at all. I don't know what the reprimand should be, whether it's a lecture or 1 detention or expulsion. But I know the felony charges are wrong based on the few facts we currently have.
ChuckMcM 14y ago
We used 2 liter bottles as the gas expansion chamber on one of our battle bots. They were good to 250 psi until some folks cut back on the amount of plastic. Then we discovered you could buy bottles headed for 'desert communities' (like Las Vegas) and those bottles had a higher pressure rating. So get your soda in Vegas kids for the most bang!
- geon 14y ago
  > 'desert communities' (like Las Vegas) and those bottles had a higher pressure rating. Any theory on why?
  - nanidin 14y ago
    They get hot... and pop! Had this happen to me with plastic bottles and aluminum cans that were sitting outside on pallets at a grocery store in the summer.
batbomb 14y ago
You know what's more awesome? Baggie bombs. The Oxy-Acetylene mixture for cutting steel, fill a ziploc bag with it. Add a few inches of newspaper, light it, run.
- fnordfnordfnord 14y ago
  Empty soda or beer cans full of oxygen and acetylene, yee haw. It sends the can tens of feet into the air, makes a loud bang like a gunshot, and makes grown men giggle like little girls.
- jrwoodruff 14y ago
  My uncle did this with trash bags. Big boom.
  - cullenking 14y ago
    I did as well (50:50 with oxygen), ignited with a shot from a roman candle. Close enough to knock me over when I was 14. Realized how fucking stupid it was when I thought about static electricity and trash bags....
    - geon 14y ago
      > static electricity My dad did bag bombs in his twenties. He was worried about them exploding while he handeled them, so he put on wool mittens to protect the hands...
  - jlgreco 14y ago
    My chemistry teacher did this with hydrogen and oxygen inside of the classroom. It was one of those "desk waste basket" trash bags rather than a proper 50-galloner but even so it was so loud I was surprised the windows didn't blow out. I think she stuck with party balloons for that demonstration from then on.
- dugmartin 14y ago
  It works even better with punching bag balloons.
pathdependent 14y ago
Around freshman year of college -- yes, college -- my roomate got an order of Omaha steaks. They were packed in dry ice. I took the dry ice; packed it in a two liter bottle; put in hot water; and, put the cap on. I stood there for about 10 seconds before I realized that a) there was no reason to think the force would be directed out the top like my weird cartoon original conception implied and b) it would take a lot of force to rip apart the two liter bottle. Immediately, I threw the bottle into our bathroom tub and me and the friend that was there with me stood about 10 feet outside the door. After two or three minutes, I started feeling silly. Nothing was going to happen. About 10 seconds later, it blew up. The metal part faucet in the bathtub was bent, and the shockwave had enough force to knock me and my friend down (although, it could have just been fear) and I couldn't hear for about two hours. This was around 2003. Not one person came by my dorm to investigate. I think if it was now, I would have been arrested. Admittedly, I was stupid, but not maliciously so.
- mixmax 14y ago
  ahh, dry ice, water and closed containers. It's a classic. I blew up stuff using this method less than a year ago.
- evilduck 14y ago
  Dry ice can be hard to acquire in some places. Luckily liquid hydrochloric acid based drain cleaners and aluminum foil are readily available everywhere and achieve the same results. 2Al + 6HCl -> 2AlCl3 + 3H2 = Boom. The only caveat is that it throws the unreacted acid everywhere, and it's pretty strongly exothermic, but I mean, you're building a small bomb so...yeah.
GigabyteCoin 14y ago
My friends and I set a tree on fire once just with some chlorine and sugar. It was a regular ritual in my hometown... gather the boys, pitch a few dollars together and buy some chlorine from the local big box stores that sold it as pool cleaner. If you mixed the chlorine and sugar together in a water bottle, and then later added water, it would explode with an impressive pop after a few seconds. We were carrying a few of these bottles in a backpack one night when suddenly, I heard a hiss. Apparently water isn't needed for a chlorine, sugar, water bomb... the jostling of the two powders together in the backpack was enough to start the reaction. By the time my friend could get the bag off his back and up to his ear to listen for himself, one of the bottles exploded. Said friend proceeded to throw the backpack as far as he could, as we all scattered in different directions. We met up later, and walked home past where we had thrown the bag earlier. All that remained was a scorched tree and a few firemen. I think that was the last time we dabbled in that sort of "fun". By the way, my friend's hearing is fine.
- greggman 14y ago
  Used to use pool acid and foil in a 2 liter soda bottle. Poor the acid in the bottle, pop a crumpled rod of foil in, seal the bottle, walk away. The foil takes a few seconds to start reacting so you have time to seal the bottle. It gets hot so the bottle starts expanding and finally pops. One time the bottle expanded but didn't pop so after waiting for a minute or two I walked up. As soon as I touched the cap it popup off and covered me with acid. I ran to the closest house and used the hose to pour water all over me. I'm guessing either because it was spent from reacting with the foil or because it's made for pools and not all that strong that I didn't get any burns. That was the last time i did it.
vidarh 14y ago
I was playing with electrolysis a lot when I was 8-9. Probably just as well I didn't think to capture the hydrogen and blow it as I'm not sure my parents would have appreciated explosions in my room. I'm not quite sure why I wouldn't have gon there - whether I just thought it too risky, or didn't realize the possibilities. I did have a series of books titled something like "hobby books for boys" my dad got in the early 60's when he was a kid that included a lot of chemistry covering various ways to make home-made fireworks and blow stuff up, which were all decidedly not considered all that acceptable to publish any more when I got them in the 80's, and I believe that's where I got my inspiration to play with electrolysis (my chemistry equipment was all originally my dads from the 60's too...). I did instead have great fun covering one of my moms silver spoons with a nice layer of lead instead after using it to stir the brine, though. Not popular. I did suggest to her that I could probably fix it by using the spoon as one of the electrodes, but she wouldn't listen.

ISL 14y ago

Elegant. Particularly for thirteen.

jules 14y ago

I'm calling bullshit. I did that many times and never blew any significant hole in the ground (though because of impatience I started using 220V -- not a great idea). Yes it makes a loud boom, but a 2 foot hole no way.

hluska 14y ago
The joy of being 12/13 is that you're still in that cusp between child and semi-adult. You've got enough motor skills and knowledge to be dangerous, but still have the childlike sense of awe that can make things look significantly larger than they are!
- masklinn 14y ago
  > still have the childlike sense of awe that can make things look significantly larger than they are! Considering some of the fishermen[0] I know, that one never goes away. [0] and guys I subsequently shared a locker room with
aarongolliver 14y ago
I agree. Though only if he used a plastic bottle. My father and I did this when I was in middle school. He (stupidly) held it in his hand. All it did was make a very loud boom, and not a two foot hole in his arm.
noonespecial 14y ago
1) Your 220 made mostly steam and little browns gas. 2) We had partially buried the bottle before setting it off.
- jules 14y ago
  Certainly, that experiment didn't last more than a tenth of a second. Lighting a 3L bottle produces about 20kJ if my calculation is correct, so if you bury the bottle in sand or other loose soil I can see how it can move that, but well then most of the hole is because you dug it. If you have a bottle full you can safely light that with the cap off while holding the bottle in your hand, though I wouldn't advise doing the same with the cap on (you certainly won't lose your hand or anything, but it may be painful). For the people wondering, here is a video: http://www.youtube.com/watch?v=HmcaC0vxaSo http://www.youtube.com/watch?v=HmcaC0vxaSo
  - noonespecial 14y ago
    Interesting. Considering we never took the cap off and lit it off with the spark, wouldn't the amount of energy in the bottle go up with the pressure? Some people were saying here that a 3 liter might take as much as 250psi. We waited until the bottle was visibly distended. How would the calculation vary with pressure? I'd be interested to know the best(worst?) case scenario!
    - geon 14y ago
      > Considering we never took the cap off and lit it off with the spark, wouldn't the amount of energy in the bottle go up with the pressure? I have been playing a bit with a potato/hairspray cannon. If you don't have a good seal (that's why you use a potato), you get no boom. I tried to shoot snow, but it would just go hsssst. I'm thinking the initial combustion raises the pressure enough for the fuel mixture to detonate, and if the seal is't good enough, the fuel will just burn gradually.
    - jules 14y ago
      The calculation is already best/worst case. I simply calculated the enthalpy of 3 liters of the mixture. The energy due to the pressure buildup is negligible. If you didn't make sure that there is no air in the bottle, then the energy would in fact be considerably lower simply because then the bottle is mostly air (the way to make sure is by submerging and filling the bottle with water and wait until the bottle is completely filled with gas, and then closing the cap under water). BTW, speaking of pressure it's unfortunate that these days the soda bottles are so thin & weak, some can't even stand 5 bar anymore, they used to be a lot thicker and stronger.

jlgreco 14y ago

> 3 liter bottle (remember those... Shasta, baby) Sometimes store-brand colas will still have 3-liter bottles. They are pretty good for bicycle-pump/bottle rockets, if anyone is interested in that sort of thing.

lotharbot 14y ago
Make sure the mouth of the bottle is the proper size for your pump assembly. Sometimes 3L bottles have extra wide mouths.

gavinlynch 14y ago

Right. But you didn't do it during school. edit: Do I really need to point out that 2 felonies for this is obviously a gross overreaction by authorities and I hope all charges are dropped? That said, if you don't agree that it was universally horrible judgement to make a drano bomb during school, then there really isn't much to discuss between us and you can carry on downvoting (although I hope none of you are in charge of my future children). my longform response: https://news.ycombinator.com/item?id=5651593 https://news.ycombinator.com/item?id=5651593

marssaxman 14y ago
Oh, come on, having horrible judgement is the whole point of being a kid. The process of growing up and becoming an adult is all about learning and acquiring good judgement. How can you expect people to gain the judgement that comes with experience without allowing them to gain that experience by trying things, some of which will turn out to be mistakes? How are they supposed to know which things are going to be the mistakes without trying some of them and thereby learning the patterns? I once did more or less the same thing as Ms Wilmot did, and you bet I did it during school, and I didn't even bother to tell anyone about my intentions first! I set up an apparatus under one of the fume hoods in the back of the chemistry lab, dissolved a bunch of aluminum, captured the hydrogen in a balloon, and then blew the whole thing up. It made a hell of a big bang, shattered a bunch of glassware, and startled the hell out of my lab-mates. Bad judgement? Well, yeah. Duh. But I didn't actually hurt anyone, and I sure learned something from the experience, and I'll bet that all my classmates learned something from it too, without having to deal with the embarrassment and clean-up that landed on my shoulders for being the nitwit who tried it. Just imagine how fucked I'd have been if I'd had to face felony charges after that. My whole life might have been different, my whole software engineering career derailed before it had even started. What a stupid waste that would have been. What a stupid waste it is going to be for all of us if this idiotic treatment of Ms Wilmot is allowed to stand.
- gavinlynch 14y ago
  Did you read my post? I do not agree with these felony charges at all. I don't know what the reprimand should be, whether it's a lecture or 1 detention or expulsion. But I know the felony charges are wrong based on the few facts we currently have.

ChuckMcM 14y ago

We used 2 liter bottles as the gas expansion chamber on one of our battle bots. They were good to 250 psi until some folks cut back on the amount of plastic. Then we discovered you could buy bottles headed for 'desert communities' (like Las Vegas) and those bottles had a higher pressure rating. So get your soda in Vegas kids for the most bang!

geon 14y ago
> 'desert communities' (like Las Vegas) and those bottles had a higher pressure rating. Any theory on why?
- nanidin 14y ago
  They get hot... and pop! Had this happen to me with plastic bottles and aluminum cans that were sitting outside on pallets at a grocery store in the summer.

batbomb 14y ago

You know what's more awesome? Baggie bombs. The Oxy-Acetylene mixture for cutting steel, fill a ziploc bag with it. Add a few inches of newspaper, light it, run.

fnordfnordfnord 14y ago
Empty soda or beer cans full of oxygen and acetylene, yee haw. It sends the can tens of feet into the air, makes a loud bang like a gunshot, and makes grown men giggle like little girls.
jrwoodruff 14y ago
My uncle did this with trash bags. Big boom.
- cullenking 14y ago
  I did as well (50:50 with oxygen), ignited with a shot from a roman candle. Close enough to knock me over when I was 14. Realized how fucking stupid it was when I thought about static electricity and trash bags....
  - geon 14y ago
    > static electricity My dad did bag bombs in his twenties. He was worried about them exploding while he handeled them, so he put on wool mittens to protect the hands...
- jlgreco 14y ago
  My chemistry teacher did this with hydrogen and oxygen inside of the classroom. It was one of those "desk waste basket" trash bags rather than a proper 50-galloner but even so it was so loud I was surprised the windows didn't blow out. I think she stuck with party balloons for that demonstration from then on.
dugmartin 14y ago
It works even better with punching bag balloons.

pathdependent 14y ago

Around freshman year of college -- yes, college -- my roomate got an order of Omaha steaks. They were packed in dry ice. I took the dry ice; packed it in a two liter bottle; put in hot water; and, put the cap on. I stood there for about 10 seconds before I realized that a) there was no reason to think the force would be directed out the top like my weird cartoon original conception implied and b) it would take a lot of force to rip apart the two liter bottle. Immediately, I threw the bottle into our bathroom tub and me and the friend that was there with me stood about 10 feet outside the door. After two or three minutes, I started feeling silly. Nothing was going to happen. About 10 seconds later, it blew up. The metal part faucet in the bathtub was bent, and the shockwave had enough force to knock me and my friend down (although, it could have just been fear) and I couldn't hear for about two hours. This was around 2003. Not one person came by my dorm to investigate. I think if it was now, I would have been arrested. Admittedly, I was stupid, but not maliciously so.

mixmax 14y ago
ahh, dry ice, water and closed containers. It's a classic. I blew up stuff using this method less than a year ago.
evilduck 14y ago
Dry ice can be hard to acquire in some places. Luckily liquid hydrochloric acid based drain cleaners and aluminum foil are readily available everywhere and achieve the same results. 2Al + 6HCl -> 2AlCl3 + 3H2 = Boom. The only caveat is that it throws the unreacted acid everywhere, and it's pretty strongly exothermic, but I mean, you're building a small bomb so...yeah.

GigabyteCoin 14y ago

My friends and I set a tree on fire once just with some chlorine and sugar. It was a regular ritual in my hometown... gather the boys, pitch a few dollars together and buy some chlorine from the local big box stores that sold it as pool cleaner. If you mixed the chlorine and sugar together in a water bottle, and then later added water, it would explode with an impressive pop after a few seconds. We were carrying a few of these bottles in a backpack one night when suddenly, I heard a hiss. Apparently water isn't needed for a chlorine, sugar, water bomb... the jostling of the two powders together in the backpack was enough to start the reaction. By the time my friend could get the bag off his back and up to his ear to listen for himself, one of the bottles exploded. Said friend proceeded to throw the backpack as far as he could, as we all scattered in different directions. We met up later, and walked home past where we had thrown the bag earlier. All that remained was a scorched tree and a few firemen. I think that was the last time we dabbled in that sort of "fun". By the way, my friend's hearing is fine.

greggman 14y ago
Used to use pool acid and foil in a 2 liter soda bottle. Poor the acid in the bottle, pop a crumpled rod of foil in, seal the bottle, walk away. The foil takes a few seconds to start reacting so you have time to seal the bottle. It gets hot so the bottle starts expanding and finally pops. One time the bottle expanded but didn't pop so after waiting for a minute or two I walked up. As soon as I touched the cap it popup off and covered me with acid. I ran to the closest house and used the hose to pour water all over me. I'm guessing either because it was spent from reacting with the foil or because it's made for pools and not all that strong that I didn't get any burns. That was the last time i did it.

vidarh 14y ago

I was playing with electrolysis a lot when I was 8-9. Probably just as well I didn't think to capture the hydrogen and blow it as I'm not sure my parents would have appreciated explosions in my room. I'm not quite sure why I wouldn't have gon there - whether I just thought it too risky, or didn't realize the possibilities. I did have a series of books titled something like "hobby books for boys" my dad got in the early 60's when he was a kid that included a lot of chemistry covering various ways to make home-made fireworks and blow stuff up, which were all decidedly not considered all that acceptable to publish any more when I got them in the 80's, and I believe that's where I got my inspiration to play with electrolysis (my chemistry equipment was all originally my dads from the 60's too...). I did instead have great fun covering one of my moms silver spoons with a nice layer of lead instead after using it to stir the brine, though. Not popular. I did suggest to her that I could probably fix it by using the spoon as one of the electrodes, but she wouldn't listen.