Why is fire hot? I always wondered what can be the composition of FIRE?

Answer 1

What your seeing is photons being emitted from the oxygen around the wood. This all has to do with the energy shells of the atoms, when the valance electron of the oxygen atom takes in energy in the form of heat (the logs are producing it through a combustion reaction) when the electron gains energy it moves up to a higher energy shell.

The thing is atoms always try to be in their least excited state. The least excited state is when all of the electrons are in the lowest shells possible.

So the excited electron in the oxygen atom will try to drop down to a lower empty energy shell. In order to do this it has to release energy, the high energy electron will release its extra energy in the form of a photon (electronmagnetic radiation), the photon is the fire we see.

The energy the electron is given determines the energy of the photon that will be released.

To understand this look at the picture in this link http://praxis.pha.jhu.edu/pictures/emspec.gif as you see from the diagram Blue is the highest energy and Red is the lowest energy. That is why at the base of the fire where it is hottest and the most energy, you see blue fire, and you see yellow and orange the furthor away the flame.

Now the reason why fire is hot, is the same reason as to why we see it. As you see from the diagram, the energy is not limited to what we can see. We can also FEEL this energy. We are feeling the photons that are in the infrared, ('infra' meaning 'before' or 'below', and 'red' indicating the colour) this sensation is what we interpret as heat, thus fire is hot. Our bodies are gaining energy from the fire.

Chris

Answer 2

Fire is hot because of the oxidation reactions going on which produce heat (and light). The actual composition of flames may be very complex because of the many stages in the reactions which occur. For a little more on fire chemistry see:
http://www.me.utexas.edu/~ezekoye/rsch.dir/firesite/science_chemistry.html

Answer 3

Fire is a chemical reaction, that releases energy. Energy being heat and light. But hey I'm an engineer, let's hear from a chemist.

Answer 4

it transfers potential energy from the wood or whatevers burning and expenses it in the form of heat energy, as far as composition, im not really sure, excelent sci question tho!

Answer 5

fire is hot gas.

the heat is released by oxidation of the various chemicals in the fuel..

its an exothermic reaction. it releases heat.

Answer 6

fire is composed by three (technicaly four) things, heat, fuel, and oxygen (also a chemical reaction is requiered).when combined, these things create fire.

Answer 7

it is a reaction to the combustion of a fuel, extreme heat and oxygen in the air

Answer 8

fire is the plasmatic state of an object/substance

Answer 9

Thats a good question but i don't think i can help

Answer 10

gas