16 replies to this topic

[Caleb]

This Saturday I am going on a one week campout. Due to fire hazards, we are not allowed to bring any fireworks to the campout on the 4th of July. But, since it will be the fourth, the scout leaders have said that we will have a contest to see who can build a fire in the most creative way. But the conditions are:

1. It cannot be explosive

2. It cannot create any hazardous materials such as chlorine or molten iron.

3. You have to be able to buy the ingredients from a local walk-in store.

Is there any fun experiments that make fire that I could use?

Btw, it would help if I could get some idea's before this Saturday. Thanks a million.

[Phi for All]

Here's a fairly safe but not very chemical idea. Using some masking tape and either wooden or book matches, you could set up an interesting kind of fuse effect where each match is close enough to light the next one in line, held together by the masking tape. If you use enough of them, it could run all the way around your kindling and really be fun to watch. The key here is to figure out how to light the first match in an interesting way. Possibly a magnifying glass (if the sun will be out at the time), or some mechanical way of having the striker light the first match (mousetrap set off by dominoes?).

[ajb]

I think I would like clarification about the forum rules here.

I know a couple of things one can get from a local chemist that will spontaneously ignite when mixed. Of course, this is not really a secret as I am sure a quick google search will reveal all.

[Phi for All]

I know a couple of things one can get from a local chemist that will spontaneously ignite when mixed.

But is a chemist the same as a "local walk-in store"? I don't think anything you can purchase from a grocery store or pharmacy that ignites when mixed would violate our HazMat policy.




Here's something that might work. If you could dip a test tube (or a dowel, a pencil or something else long but thin) in melted candle wax several times about halfway up its sides, then remove the tube, you would have a mold you could put a small amount of gasoline in. Add a candle wick to the bottom, fill it to the top with gasoline, position it in your kindling so the wick has some air and then light the wick. When the flame melts through the wax, it should release the gasoline. Assuming the gasoline doesn't douse the wick before it can ignite the fumes, it should start quite a nice fire in a very short time.

[ajb]

Ok, I do not believe I am in any violation of the forum rules here. Please correct me if I am wrong.

At your own risk.

Potassium permanganate () will spontaneously ignite when exposed to glycerine (propan-1,2,3-triol).

Assuming it is not too cold, a small pile of potassium permanganate will ignite when a drop of glycerine is added within a few moments. This can then be used to ignite other combustibles.

Both are readily available in chemist shops.

Potassium permanganate is an oxidising agent and has medical use as a disinfectant. Glycerine is used in foods and pharmaceuticals.

[Cap'n Refsmmat]

Pro tip: the ce tags let you type chemical equations, typeset in LaTeX using mhchem:

[ajb]

But is a chemist the same as a "local walk-in store"?

Don't know, but for sure it is available on the high street.

Thanks Cap'n, never did I expect to write a chemical formula down again since school!

[Caleb]

That sounds like something I could use. Thanks for the suggestion.

Btw, everything I come up with will be checked by adults. So I'm not going to try it out in the woods all alone, there will be adults there supervising everything.

---

Merged post follows:

Consecutive posts merged
Just one more quetion. What are the products of this reaction? Thanks a million!

[ajb]

I think I still got a jar of glycerine in my shed...

Long ago before international terrorism, when all you had to worry about were a few Irish I used to have lots of fun making bombs, incendiary devices, smoke bomb, etc... Not sure I would do it today.

Now my favourite weedkiller is banned in the EU.

---

Merged post follows:

Consecutive posts merged

Just one more quetion. What are the products of this reaction? Thanks a million!

See here.

[Phi for All]

Just one more quetion. What are the products of this reaction?

Here's a video. Notice they use a ventilation hood, but if you're outdoors you should be fine.

[ajb]

Apparently, this reaction is often used to ignite thermites. Not that I recommend trying to make your own thermite.

[Caleb]

That seems great! Can I just throw the products away or do I need to disspose of them spiecally?

[Phi for All]

Do you have any level B gear?



Just kidding, take along a coffee can to scoop out the leftovers from the ashes the next morning, and chuck the can in the trash.

Keep an eye on the immediate area, it looks like the reaction can spit out some hot material bits. Not a big deal.

Edited by Phi for All, 1 July 2010 - 09:45 PM.

[Cap'n Refsmmat]

That seems great! Can I just throw the products away or do I need to disspose of them spiecally?

Looking up the products, they don't look particularly dangerous, although I'd still use care to avoid getting them on your clothing or your skin. Perhaps put them in their own sealed bag.

I'm not sure of specific disposal regulations though. There may be rules.

[ewmon]

By “a local walk-in store”, I think he means readily-available, over-the-counter supplies.

METHOD 1

I’d suggest a square lantern battery wired to a bit of steel wool, but that might cause a little bit of molten steel (which would violate condition #2 in OP), and over-using the battery due to high current just might “over excite” it, resulting in a *ahem* “catastrophic failure” (which would violate condition #1 in OP). I’ve seen this done safely, and have done it safely myself, yet Scouting is Scouting, and we must follow the rules. (PS -- check with your Scoutmaster about this experiment, maybe he’ll approve it.)

METHOD 2

Justification for this method: You're near something (say a huge forest fire), and you need to start a backfire to stop the fire from advancing. Trouble is, the blaze is so hot you can't even get close enough to it to light a stick in your hand. You think to yourself, if you could just collect all that heat in one place to get it hot enough to start a fire. Hmm… then you remember a posting on a science forum …

Here’s something along the lines of unique or never-thought-of methods. Use a magnifying glass to focus the energy from a campfire onto starter material, such as paper. Use a 3-inch glass -- bigger is better. Yeah yeah, I know, it doesn’t seems unusual to start a fire with a fire, but I think no one’s ever done it this way before.

METHOD 3

Justification for this method: The sun’s just set and you need to start a fire. All you have is the very warm side of a boulder or cliff (that’s facing west into the setting sun, of course) and a magnifying glass. You think to yourself, if you could just collect all that warmth in one place to get it hot enough to start a fire. Hmm… then you remember a posting on a science forum …

If Method 2 seems too weak or obvious, try this niftier method. Put a flat solid object (such as a metal plate, cast iron frying pan, slate, flagstone, etc) against the fire, and use it as the source of heat energy to focus with the magnifying glass. When the stone becomes too hot to touch, it should be radiating enough energy to burn paper. I just invented this method, so I’m assuming this will work because we can sit in the sunlight okay and still start a fire with it, so a surface too hot to touch should definitely burn paper.

(Caution: Never put a stone in a river/water into or near a fire. Stones can become waterlogged over time, and when heated by the fire, the water can turn into steam and cause the stone to explode.)

Focal Length

For an approximation of focal length for Methods 2 and 3, use the focal length found when focusing light from the campfire. The image below shows that focal length is a function of wavelength, so the infrared focal length is even longer than that for red, thus, you’ll need to increase the focal length a bit to properly focus the heat (not light) from the fire or hot object. I have no proof that this method will work, but it seems like it “should”. Try it out first before you decide to use it.

[Caleb]

By “a local walk-in store”, I think he means readily-available, over-the-counter supplies.

Yes, that's what I mean.

---

Merged post follows:

Consecutive posts merged
I cannot get any pottasium permanganate at a chemistry store. Are there any disinfectant brands I can buy at Wal-Mart that will do?

[Caleb]

Well everyone, I was able to get some pottasium permanganate just as I was leaving for camp from a good friend. I got first place in the fire building compitition . Thanks for giving me the great idea!