What is fire? Material or energy?

Fire plays an important role, one of the most important factors in human life. Fire gives us light, heating, helps to cook food . But besides, fire is also a scary weapon, with infinite destructive power. It can destroy everything you have, even taking people's lives quickly.

1. Terrifying hypothesis about the mysterious phenomenon of "self-igniting" like a fireball
2. How is 1,000 ° C fire hose formed?

The fire burned down the house.

So, what is fire?

For the ancient Greeks, besides water, earth and air, fire was also a major element of the universe. We can see, send, feel and bring fire anywhere. But in fact, fire is not anything. While soil, water, and gas are made up of billions of atoms and remain in the same form, fire can turn to other forms.Fire is part of the chemical reactions between air oxygen and some kind of gas from gases, liquids and even solids when heated to their burning temperature.

When heated, the elements emit light. This 'light-generating heat' phenomenon is called combustion and this is why we can see the fire.

A colorful fire. Its color depends on fire and temperature materials. The hottest place has a blue flame, where the lowest temperature is yellow and orange.

Color of fire when burning different elements - from left to right: Kali, Dong, Cesi, Bo, Calcium.

The heat from the fire can keep the fuel at a burning temperature, and they will burn until the fuel runs out or the oxygen around. Compounds containing carbon and hydrogen are most flammable because they are easily combined with oxygen in the air to create CO2, water and other gases.

On Earth, the way a fire burns depends on gravity. Compared to the surrounding air, the hot air in the flame is much hotter and thinner, so they will move towards the lower pressure. Therefore, fire often spreads upwards, and there is a 'tip' when burning.

In a zero-gravity environment in space, the flame will form a sphere.

A fire is made up of many different factors:

1. Different materials will catch fire and burn at different temperatures.
2. The fire burns fast or slow depending on the size of the fuel.
3. The amount of heat generated during combustion depends on the structure of the fuel. The faster the burning rate and the more energy we have, the greater the amount of heat generated.
4. The combustion rate also depends on the shape of the fuel. Large pieces will burn more slowly than thin pieces due to their contact area with less oxygen.

So, fire from different fuels has different characteristics. And fire is not a physical or energy form but it is a rapid oxidation of a material in an exothermic chemical reaction, releasing heat, light, and other reactive products. At the same time the fire is a visible part of the fire.

The fire is classified as a plasma gas - partially ionized. To form a flame, need and enough 3 elements: combustion, oxygen and heat sources.