Naked Science Forum
General Science => General Science => Topic started by: neilep on 01/09/2007 14:39:46
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We all luff sparklers..... and ' sparkler ' manufacturers luff us luffing them !
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Nice aren't they ?
How do ' sparklers' work ?
How come they are so controlled in the way they burn ?
How hot does the sparkler get
How come the sparks don't hurt my hands ?
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I don't know why no one else has answered this, and I also don't know the details of how they are made. But I'm quite sure that the reason they don't burn your hand is this:
Temperature is different than heat. Temperature is the average molecular energy; heat is total energy. Two red hot horseshoes have twice as much heat as one red hot horseshoe. A spark can be white hot, but it's so small that it doesn't have enough heat energy to burn you. As it transfers its heat to your skin it cools off before any damage is done.
Another way to look at is, that the heat something "contains" is the amount of energy that's needed to get it up to a certain temperature. Of course the same amount of energy is released when it cools. Obviously, two red hot horseshoes tossed in a pail of water will will warm the water twice as much as one horseshoe. And a cup of boiling water can put you in the hospital, while a teeny bit of white hot metal won't.
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I guess you would need an oxidiser, something to act as a fuel and then something to bindthem all together. Perhaps a passing chemist will know exactly what they are?
I reckon the sparkly bit that shoots around is magnesium or zinc. Wow what i lot of help i'm not.
One thing i do know, i can make nice sparkler effects with my cigarettes.
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Like most fireworks sparklers are a basic gunpowder mix (nitrates plus suphur and charcoal) containing a few additions to produce the colours and effects in the flame. the mix burns quickly and is very hot. Look at the metal core of a sparkler and you will see it gets bright red hot and sometimes bends with the heat. I think that the sparkly bits are probably finely divided iron filings because they look very like the sparks you get when you grind steel with a fast grindstone The mixture has been damped to make it a bit like putty and formed on the iron wire and then allowed to dry to form the sparkler.
sparklers can be very dangerous if misused the sparks themselves are very hot but small and dont burn for long but they will burn the lint on the surface of fabric.
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I don't know why no one else has answered this, and I also don't know the details of how they are made. But I'm quite sure that the reason they don't burn your hand is this:
Temperature is different than heat. Temperature is the average molecular energy; heat is total energy. Two red hot horseshoes have twice as much heat as one red hot horseshoe. A spark can be white hot, but it's so small that it doesn't have enough heat energy to burn you. As it transfers its heat to your skin it cools off before any damage is done.
Another way to look at is, that the heat something "contains" is the amount of energy that's needed to get it up to a certain temperature. Of course the same amount of energy is released when it cools. Obviously, two red hot horseshoes tossed in a pail of water will will warm the water twice as much as one horseshoe. And a cup of boiling water can put you in the hospital, while a teeny bit of white hot metal won't.
This is wonderful.
THANK YOU Billjx.
Your explanation of the differentiation between heat and temperature is something I would not have considered. But now that you have explained it...it's obvious.
I imagine in the case of sparklers...the 'light' is bigger than the spark !
THANK YOU VERY MUCH
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I guess you would need an oxidiser, something to act as a fuel and then something to bindthem all together. Perhaps a passing chemist will know exactly what they are?
I reckon the sparkly bit that shoots around is magnesium or zinc. Wow what i lot of help i'm not.
One thing i do know, i can make nice sparkler effects with my cigarettes.
Cool !!...EWE are a lot of help !!.....So, how do ewe turn a ciggy into a sparkly ?
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Like most fireworks sparklers are a basic gunpowder mix (nitrates plus suphur and charcoal) containing a few additions to produce the colours and effects in the flame. the mix burns quickly and is very hot. Look at the metal core of a sparkler and you will see it gets bright red hot and sometimes bends with the heat. I think that the sparkly bits are probably finely divided iron filings because they look very like the sparks you get when you grind steel with a fast grindstone The mixture has been damped to make it a bit like putty and formed on the iron wire and then allowed to dry to form the sparkler.
sparklers can be very dangerous if misused the sparks themselves are very hot but small and dont burn for long but they will burn the lint on the surface of fabric.
THANK YOU IAN.
Yes, I have always noticed how extremely hot the sparker becomes. There is clearly quiet a violent but controlled reaction happening !
Could it be something like an exaggerated firework fuse going off ?..I gather it would be difficult to put out by blowing alone !
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I love them too and all the rest of the fireworks with them!
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How Does it Work?
Let's put it all together: A sparkler consists of a chemical mixture that is molded onto a rigid stick or wire. These chemicals often are mixed with water to form a slurry that can be coated on a wire (by dipping) or poured into a tube. Once the mixture dries, you have a sparkler. Aluminum, iron, steel, zinc or magnesium dust or flakes may be used to create the bright, shimmering sparks. The metal flakes heat up until they are incandescent and shine brightly or, at a high enough temperature, actually burn. A variety of chemicals can be added to create colors. The fuel and oxidizer are proportioned, along with the other chemicals, so that the sparkler burns slowly rather than exploding like a firecracker. Once one end of the sparkler is ignited, it burns progressively to the other end. In theory, the end of the stick or wire is suitable to support it while burning.
Sparkler Chemistry
A sparkler consists of several substances:
* An oxidizer
* A fuel
* Iron, steel, aluminum, or other metal powder
* A combustible binder
In addition to these components, colorants and compounds to moderate the chemical reaction also may be added. Often, firework fuel is charcoal and sulfur. Sparklers simply may use the binder as the fuel. The binder is usually sugar, starch, or shellac. Potassium nitrate or potassium chlorate may be used as oxidizers. Metals are used to create the sparks. Sparkler formulae may be quite simple. For example, a sparkler may consist only of potassium perchlorate, titanium or aluminum, and dextrin.
Reaction Details
Now that you've seen the composition of a sparkler, let's consider how these chemicals react with each other:
Oxidizers
Oxidizers produce oxgen to burn the mixture. Oxidizers are usually nitrates, chlorates, or perchlorates. Nitrates are made up of a metal ion and a nitrate ion. Nitrates give up 1/3 of their oxygen to yield nitrites and oxygen. The resulting equation for potassium nitrate looks like this:
2 KNO3(solid) --> 2 KNO2(solid) +O2(gas)
Chlorates are made up of a metal ion and the chlorate ion. Chlorates give up all of their oxygen, causing a more spectacular reaction. However, this also means they are explosive. An example of potassium chlorate yielding its oxygen would look like this:
2 KClO3(solid) --> 2 KCl(solid) + 3 O2(gas)
Perchlorates have more oxygen in them, but are less likely to explode as a result of impact than are chlorates. Potassium perchlorate yields its oxygen in this reaction:
KClO4(solid) --> KCl(solid) + 2 O2(gas)
Reducing Agents
The reducing agents is the fuel used to burn the oxygen produced by the oxidizers. This combustion produces hot gas. Examples of reducing agents are sulfur and charcoal, which react with the oxygen to form sulfur dioxide (SO2) and carbon dioxide (CO2), respectively.
Regulators
Two reducing agents may be combined to accelerate or slow the reaction. Also, metals affect the speed of the reaction. Finer metal powders react more quickly than coarse powders or flakes. Other substances, such as cornmeal, also may be added to regulate the reaction.
Binders
Binders hold the mixture together. For a sparkler, common binders are dextrin (a sugar) dampened by water, or a shellac compound dampened by alcohol. The binder can serve as a reducing agent and as a reaction moderator.