What substance is fire and what form is it in?

Objects in nature generally exist in three forms: solid, liquid, and gas, but fire doesn't seem to fit into any of these three categories. So what exactly is fire? What form does it take?

In fact, fire is a special form.

The fire we see is better called flame. It appears in the form of plasma, which is the fourth form of matter. It looks a bit like gas, so it is also called supergaseous state. So what is plasma? The matter we see is composed of molecules and atoms. Atoms include negatively charged electrons outside the nucleus and positively charged nuclei. When the temperature of a substance is too high or for other reasons, the electrons outside the nucleus absorb energy, get rid of the constraints of the nucleus, and become free electrons. The substance becomes free electrons and charged ions. The substance in this state is called plasma.

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The fire, lightning, aurora, etc. on Earth are all forms of plasma.

lightning

aurora

Where did the fire come from?

There is a story in Chinese mythology about Suiren drilling wood to make fire. As ancient humans had no fire, they often fell ill and had a short life span. The god Fuxi could not bear it and told humans that there was fire in Suiming country. Later, young people went to Suiming country and drilled wood under the Suimu tree to get fire. Archaeologists have found that early apes living in Kenya, East Africa, had used fire three million years ago. Traces of fire were also found at the Yuanmou Man site in China. Since its discovery, fire has brought many benefits to humans. Primitive people used fire to drive away wild beasts and learned to roast food with fire. The light of fire also brought light to humans. Even in the dark, people can see things clearly.

Drilling wood to make fire

Early apes used fire

So what is the essence of fire?

From the perspective of modern science, fire is a strong oxidation reaction during the combustion of substances, and its energy is released in the form of light and heat. In other words, fire is actually a form of energy, and the essence of fire is a mixture of hydrogen, carbon, oxygen and other substances. If you want to make a fire, you need combustibles, high enough temperature and oxidants, all three of which are indispensable.

Since the fireball is made of matter, does the fire have weight? Why do the flames we see all run upwards?

Fire has weight and is affected by the Earth's gravity. The reason we see flames rise is because of the hot air around the flames. The hot air pushes the flames upward as it rises, and if a fire is lit in outer space, it will be in the shape of a sphere.

In addition, the colors of flames produced by different combustibles are also different. Natural gas burns with a blue flame, while candles burn with an orange-red flame. In addition to the different components of the substances themselves, it is also related to the degree of combustion of the combustibles. When the substance is fully burned, it is generally a blue flame. Incomplete combustion is like a candle. In fact, the core of the red flame is also blue, but because it is wrapped by the outer red flame, the blue part is often not observed. The outer red flame is because the carbon black produced during combustion floats above the flame, so it is mostly displayed as red.

After reading this, do you have a certain understanding?

Source: Cosmic Decoding