Outforia Quicktake: Key Takeaways
- Fire temperatures can range from 600 °C to 3,000 °C, varying based on factors such as the oxidizing agent used and the concentration of the said agent.
- The color of a fire can offer a rough estimate of its temperature: red flames are about 704–982 °C, orange flames are roughly 1,149–1,204 °C, yellow flames are about 1,260–1,427 °C, white flames are around 1,427–1,648 °C, and blue flames are over 1,649°C.
- Fire is a result of an exothermic reaction involving an oxidizing agent, heat, and a catalyst, often referred to as the “fire tetrahedron” or fire triangle.
- The color of flames can be influenced by the substances burning; for example, sodium can make flames look yellow, while copper makes them turn green.
- The heat of a fire primarily comes from the energy released by the oxidizing agent. The type of fuel also influences the fire temperature, but not as significantly as the oxidizing agent.
Anyone who’s watched a glossy magazine burn will be aware of the amount of chemicals used in printing. It glows in rainbow hues of green, pink, and violet.
Some of these chemicals are harmful to the environment or pollute the air, however.
With that said, not all fires are created equal. Fire temperatures can range from 600 °C to 3,000 °C. And this temperature can change depending on different things.
You can change the color and temperature of fire by adding chemicals or using a different oxidizing agent. You can also alter the amount of the oxidizing agent. This usually means oxygen.
Want to know how hot a fire is? And how do the temperature and color of fire change?
Are All Flames the Same Temperature?
No, some flames can be hotter or colder than others. For instance, there are several ways to raise the temperature of a fire:
- Using pure oxygen (or another oxidizing agent ) instead of air
- Using high-energy fuel such as acetylene
- Stopping heat radiation loss to the surroundings
- Using neither too much nor too little oxygen,
Can You Spot a Fire’s Temperature with Your Eyes?
Although it’s not foolproof, you can roughly guess the temperature of a fire just by looking at it. It’s all about understanding a bit of fire science and matching flame colors to their typical temperatures.
Here’s the lowdown: fire happens when something burns, creating heat, light, and other products like water vapor and carbon dioxide.
The flame you actually see is made up of super-hot gases. The color of those flames and how bright they are can give you a hint about how hot the fire is.
Different flame colors show up because of how hot the fire is. The color changes based on a nifty thing called black body radiation—basically, the color changes as the heat cranks up.
Here’s a quick rundown of what flame color relates to which temperature:
|Color||Temperature Range (°C)|
|Blue||1,649 and above|
Keep in mind, though, that different stuff burning in the fire can change the flame color. Like sodium, sodium can make flames look yellow, while copper makes them turn green.
So, while flame color is a neat party trick to estimate a fire’s temperature, it’s not very accurate.
For a precise temperature check, you need gadgets like temperature sensors or thermal imaging devices.
You May Also Like: How Hot Is A Campfire? Wood Tips, Temperature, Color Facts
Why is Fire Hot?
Fire is hot because of the energy released by the oxidizing agent. Most of the time, this is oxygen.
The heat comes from the double bond of the oxygen atom being broken and replaced with stronger bonds to other substances.
It’s the oxidizing agent that plays the most crucial part in the exothermic reaction. So it’s mostly the amount of oxygen, not the type of wood or coal, that controls the temperature of a fire.
The type of fuel does make a difference, but not as much as the oxidizing agent.
Share This Image On Your Site
<a href="https://outforia.com/how-hot-is-fire/"><img style="width:100%;" src="https://outforia.com/wp-content/uploads/2023/10/how-hot-is-fire-infographics-10082023.jpg"></a><br>How Hot Is Fire Infographic by <a href="https://outforia.com">Outforia</a>
What is Fire?
Fire happens when an exothermic reaction takes place. This is a reaction that gives out heat. It’s a chemical reaction where an element gets oxidized.
The element loses its electrons to create heat, chemicals, light, and even sound in some cases.
An endothermic reaction is the opposite. Endothermic reactions absorb heat. Cold packs keep the surroundings cool by using ammonium nitrate dissolved in water. This creates a chemical reaction that absorbs heat.
You May Also Like: Bonfire Vs Campfire: What’s The Difference?
How Does Fire Happen?
Fire is a chain reaction in the presence of an oxidizing agent, heat, and a catalyst. It requires all three elements in order to burn. This is otherwise known as the “fire tetrahedron,” or fire triangle.
While this sounds complicated, all it means is that you need oxygen or another flammable gas, heat, and something with a spark to light the fire. There’s one other thing you need to light a fire: gravity.
1. Flammable Gas
Oxidizing agents react by removing electrons from other substances. They also have a reverse reaction, known as reduction.
In reduction, electrons are added to other substances. These two reactions always happen together. This process is known as oxidation reduction.
Oxygen is the most well-known oxidizing agent, but there’s plenty more, such as:
- Ammonium dichromate
- Ammonium perchlorate
- Ammonium permanganate
- Barium peroxide
- Calcium chlorate
- Chlorine gas
Heat energy can be created in many ways. Kinetic energy transforms into heat when we exercise. This comes in handy when we light a fire using friction, like spinning a stick with a bow drill.
Electrical energy converts into heat. If enough voltage goes through something, it will catch fire. This is how you can start a fire with a battery. This is also why we have fuses in our household electrics.
Heat can be created by a chemical reaction. This is what happens when you use potassium permanganate, vegetable glycerin, and even water to start a fire.
A catalyst is a substance that allows a chemical reaction to proceed. In the case of fire, your trusty lighter is the catalyst. More specifically, the flint or electrical spark inside is the catalyst.
Catalysts are unchanged at the end of the chemical reaction (fire). They start the process, but then their job is done.
So, why do we need gravity to light a fire? Without gravity, a fire rapidly uses up its supply of oxygen. The oxygen would dissipate, and the fire would be put out.
Oxygen moves towards the fire when gravity enables a process known as thermal convection.
Thermal convection happens when a fluid moves past a solid that is at a different temperature. It can only happen in the presence of gravity.
This is why the most dangerous part of space flight is at the beginning, when the craft moves through the atmosphere. Fires are much more likely at this time. It’s hard for a fire to start in zero gravity once the craft is in space.
Different Flame Colors and Temperatures
Flames that look black at the edges involve heating up sodium. The middle of the flame is orange, like a normal streetlamp, but the edges look black to us.
This happens because the wavelength of the sodium electrons both produces an orange color and absorbs it. The absorbed wavelengths look black to our eyes.
Blue flames come from burning hydrocarbon gas or alcohol. A blue flame means there is enough oxygen to completely combust the gas.
Methane and propane burn blue, but at slightly different temperatures. Methane burns at 1,960 °C, while propane burns at 1,980°C. That’s only a 20°C difference, so you won’t notice it much if you’re cooking.
Pink flames are made in two ways. In fireworks, pink is made by mixing two chemical reactions together in one firework:
Magnesium (burns white) + Strontium or Rubidium (burns red) = Pink Fireworks
Pink can also be made by reducing the intensity of a red firework. This is done by adding nitrates.
In some situations, you’ll need to make the colorant more accessible to the flames. You do this by dissolving it in methanol or a mixture of water and adding it to a stronger solution of alcohol.
The safest way to make green fire is to add copper sulfate. You can find copper sulfate in tree stump removal and algae control products.
Other chemicals also burn green, but they are not as safe. Copper sulfate does kill algae, but it’s commonly used in schools for children to grow crystals.
You May Also Like: How To Dispose Of Camping Propane Tanks
If you’re having trouble wrapping your head around the different temperature measurements in this article, here’s a list of things you can compare them to:
|Summer Day||Up to 37.8|
|Pizza Oven||Up to 426.7|
|Lava||704 to 1,204|
|Surface of the Sun||About 5,500|
How Hot Is Fire FAQs
Is anything hotter than fire?
Lightning is a stream of photons, otherwise known as plasma. It can reach 27,000 ºC. That’s five times hotter than the sun’s surface.
Scientists have managed to create temperatures of 4,000,000,000,000 ºC (4 trillion degrees) in the Large Hadron Collider, but only for a few microseconds.
Is the sun on fire?
The sun is not actually on fire. Fire is defined as burning in the presence of oxygen or an oxidizing compound. There’s no oxygen in the sun. Instead, hydrogen is being turned into helium by the process of nuclear fusion.
Which burns hotter, charcoal or wood?
Charcoal burns hotter than wood. This is because the water, sap, and non-combustible parts of the wood have already burned away. This leaves the fire with less ‘work’ to do to combust the remaining fuel.
Is there a fire that won’t burn you?
Nitrocellulose is a substance that burns so quickly that your skin doesn’t get damaged. It’s used in magician’s tricks as well as explosive mixes and gunpowder. It’s still not safe enough for untrained people to try at home.