“Hot” means “containing things of high energy” – so particles that are moving fast, and radiation that is of high energy and reactive chemical species. Fire contains all that. So the word “fire” kind of MEANS “hot”!
But if you stick your hand into it (don’t) I guess you’re asking “Why does it hurt”. The fire does damage to your hand, so you feel pain. What’s the damage? The damage is caused by the heat (which is radiation – so like the sun’s heat, but more intense). It’s also caused by heat of the molecules in the air/flames/gas which are moving VERY fast – they will collide with your hand and damage the molecules there. And there are very reactive chemical species in there (actually atoms which are in a very bad way and in need of combining with something as soon as they can) which will also seriously damage the molecular structure of your skin. A combination of all this stuff will be enough to rip apart the molecules in your hand, including the nerves, and you get a serious Ouch. Fire contains a lot of things you really don’t find elsewhere in nature, so the chemistry is quite odd.
Fire is the result of a chemical reaction. Oxygen combines with the fuel (wood, candle wick etc) and energy is released as heat and colour. Other chemicals are released as well, and give colour to the flame (the colour will depend on what kind of chemicals are released).
Reactions which release heat are called exothermic, and reactions which suck in heat and make the surrounding air cold are endothermic (eg. one of those ice packs that you break and it goes cold).
Some chemical changes store up energy. Some chemical changes release the stored energy. Fire feels hot because when fuel (wood or oil or paper, etc) react with air, the chemical changes release stored energy.
Fire is a visual display of a chemical reaction that is happening. The chemical reactions happening are releasing stored energy as heat and colour while making new things like gases and ash.
The flames that you can see in a fire are because the energy is being released as light. Here is the interesting thing about light. It is part of the electromagnetic spectrum. This spectrum is a range of all possible frequencies of electromagnetic radiation. Light is one type of electromagnetic radiation and makes up a small part of the spectrum. http://en.wikipedia.org/wiki/File:EM_Spectrum_Properties_edit.svg
Fire not only releases light but it also releases infrared radiation. This type of radiation is the warmth that we can feel from the fire. It’s the part that makes fire hot.
emma
“Hot” means “containing things of high energy” – so particles that are moving fast, and radiation that is of high energy and reactive chemical species. Fire contains all that. So the word “fire” kind of MEANS “hot”!
But if you stick your hand into it (don’t) I guess you’re asking “Why does it hurt”. The fire does damage to your hand, so you feel pain. What’s the damage? The damage is caused by the heat (which is radiation – so like the sun’s heat, but more intense). It’s also caused by heat of the molecules in the air/flames/gas which are moving VERY fast – they will collide with your hand and damage the molecules there. And there are very reactive chemical species in there (actually atoms which are in a very bad way and in need of combining with something as soon as they can) which will also seriously damage the molecular structure of your skin. A combination of all this stuff will be enough to rip apart the molecules in your hand, including the nerves, and you get a serious Ouch. Fire contains a lot of things you really don’t find elsewhere in nature, so the chemistry is quite odd.
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Fire is the result of a chemical reaction. Oxygen combines with the fuel (wood, candle wick etc) and energy is released as heat and colour. Other chemicals are released as well, and give colour to the flame (the colour will depend on what kind of chemicals are released).
Reactions which release heat are called exothermic, and reactions which suck in heat and make the surrounding air cold are endothermic (eg. one of those ice packs that you break and it goes cold).
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Some chemical changes store up energy. Some chemical changes release the stored energy. Fire feels hot because when fuel (wood or oil or paper, etc) react with air, the chemical changes release stored energy.
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There’s lots of things that happen in a fire.
Fire is a visual display of a chemical reaction that is happening. The chemical reactions happening are releasing stored energy as heat and colour while making new things like gases and ash.
The flames that you can see in a fire are because the energy is being released as light. Here is the interesting thing about light. It is part of the electromagnetic spectrum. This spectrum is a range of all possible frequencies of electromagnetic radiation. Light is one type of electromagnetic radiation and makes up a small part of the spectrum. http://en.wikipedia.org/wiki/File:EM_Spectrum_Properties_edit.svg
Fire not only releases light but it also releases infrared radiation. This type of radiation is the warmth that we can feel from the fire. It’s the part that makes fire hot.
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