Wood Won't Melt, Ice Won't Burn: Exploring Melting and Burning

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In summary, wood doesn't melt and ice doesn't burn because they have different chemical compositions and different boiling points.
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Scott 224
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Why doesn't wood melt and ice burn?
 
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  • #2
Scott 224 said:
Why doesn't wood melt and ice burn?
Also please let me know if I posted this in the right category (I'm new).
 
  • #3
I don't know about wood, but ice doesn't burn because it is already burnt. Water is the result of the complete combustion of hydrogen. Once something is completely burned it no longer has any additional energy to release via combustion.
 
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  • #4
Dale said:
I don't know about wood, but ice doesn't burn because it is already burnt. Water is the result of the complete combustion of hydrogen. Once something is completely burned it no longer has any additional energy to release via combustion.
Thanks for the explanation. :)
 
  • #5
Scott 224 said:
Why doesn't wood melt and ice burn?
Melting is the disassociation of molecules that are in a crystal lattice. It is a transition from solid to liquid. Wood doesn't HAVE a crystal structure nor does it have a liquid state so the concept of melting doesn't apply to it. If you apply energy to wood, in the form of heat, you can't get "melting" you just get burning.
 
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  • #6
phinds said:
Melting is the disassociation of molecules that are in a crystal lattice. It is a transition from solid to liquid. Wood doesn't HAVE a crystal structure nor does it have a liquid state so the concept of melting doesn't apply to it. If you apply energy to wood, in the form of heat, you can't get "melting" you just get burning.
Thanks for the answer
 
  • #7
The key here is to understand that a combination of chemicals (groups of molecules or atoms) may be able to interact with each other and recombine in such a way as to release energy in the form of heat and light. For example, the chemicals that make up wood, such as the carbon and hydrogen in various hydrocarbon molecules, are able to interact with the oxygen in the air to form carbon dioxide and water. Both carbon dioxide and water are more "tightly bound" than the oxygen and hydrocarbon molecules were prior to the reaction and so their reaction with oxygen releases energy. To turn these chemicals back into the original oxygen and hydrocarbon molecules, you'd have to add energy.

Water, on the other hand, is already more tightly bound than the oxygen in the air and will not spontaneously react with it. In other words, there are no combinations (that I know of) of atoms or molecules that a reaction between water and oxygen could create that would release energy. Not only that, it takes so much energy just to break water molecules apart that you have to heat them to very high temperatures before they start to dissociate.

Ice is composed of water molecules bound to each other in a crystal structure, and heating ice to the melting point doesn't provide nearly enough energy to break apart the water molecules themselves. However, it does provide enough energy to the molecules to break the strong hydrogen bonds they have with each other, forming a liquid of freely moving water molecules without a structure. Heat the water up even higher and the molecules acquire enough energy to break apart from each other completely and turn into a gas.

Another thing to note is that wood is composed of a large number of different chemicals, with different melting and boiling temperatures and the potential to react with each other even if placed in an inert atmosphere lacking oxygen. By the time you heated the wood to a high enough temperature to melt everything, you'd likely have triggered a number of different chemical reactions in the wood.
 
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  • #8
Scott 224 said:
Why doesn't wood melt and ice burn?

Before that can be answered you must first understand why ice melts and wood burns. Once you do that you will see that the circumstances under which ice melts can never apply to wood. And the circumstances under which wood burns can never apply to ice.

Some of the answers already posted have provided a lot of that information, but note that that's all any answer can ever provide to questions like this.
 
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1. What is the difference between melting and burning?

Melting and burning are two different physical processes that involve changes in the state of matter. Melting is the process of changing a solid into a liquid, while burning is the process of a substance reacting with oxygen to produce heat and light.

2. Why does wood not melt?

Wood is primarily made up of cellulose and lignin, which have high melting points. This means that they require a lot of heat to break down into a liquid state. Additionally, when exposed to high temperatures, wood undergoes a chemical process called pyrolysis, which causes it to break down into smaller molecules instead of melting.

3. Can ice burn?

No, ice cannot burn because it is already in its solid state. Burning requires the presence of oxygen, which is not present in solid ice. However, ice can melt when exposed to heat, which can then lead to burning if other flammable materials are present.

4. What factors affect the melting and burning points of a substance?

The melting and burning points of a substance can be affected by various factors, such as the chemical composition of the substance, pressure, and the presence of impurities. For example, adding impurities to a substance can lower its melting point, while increasing pressure can raise both the melting and burning points.

5. How does the process of melting and burning contribute to the Earth's cycles?

Melting and burning play important roles in the Earth's cycles, such as the water cycle and the carbon cycle. Melting of ice and snow leads to the formation of rivers and lakes, which are essential for sustaining life on Earth. Burning of fossil fuels and plant matter releases carbon dioxide into the atmosphere, which is then absorbed by plants through photosynthesis, contributing to the carbon cycle.

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