Why is the flame of gas burning blue?

When cooking and cooking with gas, we will find that there is a blue flame when gas burns, while the flame when wood burns is not blue, but red. Why do the same flames have different colors? The color of fire is different at different temperatures. Usually, the color of fire has the following relations with temperature: dark red: about 600℃; Deep red: about 700℃; Orange: 1000 or so; Pure orange: 1 100 or so; Golden orange: about1200℃; Golden yellow: about1300℃; Golden white: about1400℃; Pure white: about1500℃; White blue:1above 500℃. People often say that "the fire is perfect" means that the temperature of the fire is high. When the temperature of the fire exceeds 2000℃, the color of the fire is cyan. Flame can be divided into outer flame and inner flame. The outer flame refers to the layer outside the flame, which can be exposed to a lot of oxygen and can be fully burned, so the temperature of the outer flame is higher than that of the inner flame. The temperature of wood burning is lower than that of gas, so the light emitted is close to red, while the temperature of gas flame is very high, so the light emitted is close to blue.