Physics Experiment With Exploding Sledgehammer




Introduction: Physics Experiment With Exploding Sledgehammer

About: None of it is for profit.

Here is more information about the tradition of exploding hammers:
Thanks to someone reading the comments, I have located the person responsible for shooting the video. They have been sent a link in case they are not happy with this use.
The Ideal Gas law (pV=nRT) was first stated by Benot Clapeyron in 1834. Basically, from it we can deduct that if you compress a material quickly, it generates heat because of friction between the gas molecules.

In fact, this principal is what powers diesel engines. Of course, there are no gasses involved in the base explosives, the Ideal Gas law is cited here because it demonstrates the relationship between friction and heat. What triggers the detonation is a combination of shockwave and internal friction - that's why you have to use fireworks with chlorates or perchlorates in them (thanks kiteman).

Instead of a spark plug to ignite the fuel, diesel engines have a glow plug to heat the fuel to a critical temperature. It is the compression from the stroke of the piston itself that causes the final ignition!

In this instructable we will show you how to illustrate this principal while building an exploding sledgehammer. Be careful as this may be illegal and/or very dangerous.

Step 1: Materials

Sledgehammer, fireworks, masking tape. You'll need a sledgehammer of decent size. It must have a business end heavy enough to combust the explosives and a handle
long enough to give you distance from the explosion (for safety).

The fireworks can be anything that contains, mixtures of potassium chloride and sulphur. Many do. Regular gunpowder may work, too. The masking tape can be substituted with other kinds of sticky tape.

Step 2: Taping Things Together

Tape the fireworks on one end (and one end only) of the sledge hammer. Make sure they are bundled tight so that the sledgehammer will deliver all
it's energy into them. If you're just getting started, a mound of firecrackers the size of an altoids box will deliver a decent whollop.

More advanced makers can use a pile as large as wireless router. But be advised, if the pile is too big you will have trouble generating the
compression required to ignite them all at once. And it can become unsafe at larger sizes.

Step 3: Location and Safety

Find a flat, hard surface to strike upon. If all you have is dirt, you might have better results by using a small tile. Earplugs are strongly recommended! Be safe!

Step 4: Detonation and Afterthoughts

Warning! This may be illegal and may be unsafe in your area. Please do not do this if it is unsafe or illegal!

With all of your friends watching, strike the hard surface with the end of the sledgehammer that has the fireworks taped to it.
Prepare for a boom!

Hopefully you have had fun and learned about the ideal gas law pV=nRT.
Also hopefully you still have your hearing and are safe and unharmed!



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    The ideal gas law doesn't apply here, and it rarely applies anywhere because gases rarely obey they law and exhibit ideal behaviour. You just lifted this off YouTube didn't you? L

    16 replies

    Beg to differ. From the ideal gas law we can infer the relationship between heat and pressure. That's relevant to what's happening here. As a law of physics, it is present even when the conditions to observe it are not.

    No begging, just differing - none of the components of those fireworks are gases until after ignition.

    What triggers the detonation is a combination of shockwave and internal friction - that's why you have to use fireworks with chlorates or perchlorates in them (the chlorides are just there to add colour).

    Anyway, since you just lifted this off YouTube (or are you also known as "Djangosama"?), it's flagged for breaking copyright.

    thanks for the additional info, I've added it to the description. However, flagging is a mean thing to do. the idea that everything is automatically copyright, including a video taken in another country by some tourist who never claimed copyright, which has already been circulated all over the internets under dozens of aliases, well... conforming to that standard is killing free culture.

    Just because somebody else did it does not make it right for you to do it.

    (Have you any idea how many times a day I have to listen to the excuse but he did it first, Sir!?)

    You lifted it without even crediting where you lifted it from. You presented it as your own project, as if you had actually done it, yet you didn't even have the sense to work out what is really going on in the video, and what is really in the fireworks they use. It's not just stolen, but stolen lazily.

    There are rules here about copyright. I am not flagging to be mean, I am flagging to maintain the credibility of this site.

    For the sake of your account, I strongly suggest you unpublish this project. If You want to try recreating it yourself, fair enough, go for it. Take pictures and publish away, but as it stands this project is dishonest.

    Ask yourself: "do I really need to suck the joy out of big explosions?" Thanks to someone reading this discussion, I have located what I believe to be the original poster. I updated the youtube link to point to their station. I have also contacted them in english and spanish and offered to remove this instructable if they do not like it. Kiteman, let us not sacrifice shared culture on the altar of copyright more than we need to. They have taken enough from us. I've shared this with past employees of this site who took it with the appropriate grain of salt. You can do the same.

    This isn't culture, it's copyright violation. Feel free to enjoy explosions, but you would have received a much more appreciative reception if you had been honest and posted this as a forum thread along the lines of "look what I found on youtube", instead of dishonestly attempting to present it as your own work in an Instructable. If you are finally attempting to do the right thing, I would expect you to unpublish this "instructable" until you have permission from the original video's owner to present it as an Instructable, or until you have reproduced yourself and taken photos and video.

    I'm happy with the reception this has received from the majority of people.

    I guess you're failing maths as well as chemistry and law? 2 out of six commenters is not a majority. Even less so when you consider the tens of thousands of members who not even to look at your project.

    Out of the >500 viewers, 1 fairly level headed commenter was moved to leave vaguely negative comments and 1 pedant has complained very loudly. I'm happy with that.

    (It's not appropriate as an Instructable, it could have been posted otherwise)

    The joy of big explosions is all over the internet, if you've got an original idea show us it (please).


    Keep following me, I'll be posting some interesting stuff. Not every one will be a masterpiece but the ones that aren't will at least be entertaining ;)

    Someone is detonating fireworks by hitting them with a hammer. This is most likely to be causing ignition by friction or shock, gas laws hardly come into it. How old are you? And you just lifted this off YouTube didn't you? L

    I hereby accuse you of replying without reading the rest of the comments. Your input is appreciated, but consider that you might be taking this a little too seriously.

    I read the rest of the comments, but didn't see anything useful at the time - cached page perhaps?

    Anyhow, you didn't do anything here - it's not an original piece of work. Post it in a Forum maybe, but don't try to turn this into a "How to".

    By asking you age, I meant "are you likely to be doing this sort of crazy thing"?!


    Oh, no, I would never do something so dangerous without safety goggles.

    (ha ha)

    But you would?


    LOL! BEST! SPORT! EVAR!!!!!, who got hit by the flying sledge hammer? I saw this vid a while ago. Did it come from you? Where is it from?

    That was a silly thing to do.