What is fire made of?

TravelJunkie

I'm not a scientist, and this question my 5 year old posed had me stumped.

Its a chemical reaction that causes heat is all I could come up with... but that's not what its made of.

Anything you guys can add?

Tx

ClutchIt

I'm guessing that it is light given off by the atoms and molecules that become hot due to the fuel being burnt in an exothermic reaction (Reaction that gives off heat).

OK thats a bit confusing...

When something is burnt the air and stuff around it becomes hot. When things become hot they can change colour. That's my guess but I'm only guessing, I'm sure someone here will give a proper explanation.

cianl1

Fire is the combination of three factors. Heat, oxygen and fuel. If one is not present then, no fire.

Fire is the rapid oxidation of combustible material which releases energy (in the form of heat and light) and other products of the reaction, most commonly carbon dioxide.

The flame itself is a mixture of reacting gases and or solids (i.e. oxygen and your fuel) that emit visible and infra-red light.

As an aside, the colour of the flame depends entirely on the electronic structure of the material being burned. Most organic materials, such as wood, burn with the normal bright yellow-orange flame however lithium emits a sharp crimson flame,sodium a pure yellow flame and potassium a strong lilac colour.

That should do it.

TravelJunkie

Thanks for the explanation Cian. Now I know why gas burns different colour too!

But to simplify for the 5 year old...

Fire is heat that reflects light when something like wood or petrol burns? And it is made of gases.

Mountjoy Mugger

Is fire not energy?

ClutchIt

Mountjoy Mugger wrote: »

Is fire not energy?

No. Heat is energy. Fire is sometimes a by-product of the release of heat during a chemical reaction (burning something).

cianl1

TravelJunkie wrote: »

Thanks for the explanation Cian. Now I know why gas burns different colour too!

But to simplify for the 5 year old...

Fire is heat that reflects light when something like wood or petrol burns? And it is made of gases.

Nearly right. It gives off light and heat when the fuel burns and the flame is made of the combined oxygen and fuel burning together.

Happy to help!

amen

electronic structure of the material being burned

would it not have been easier to say the elements that are involved in material as this is a term more recognisible by the majority of people?

cianl1

Perhaps, but one point I would raise is that this is the dedicated Physics & Chemistry forum and as such there may be "technical talk", so to speak. Plus, 4 years in a degree course turns you pedantic.