You think probable to a diffusion flame.
An open flame above an air hole on a Bunsen burner is called a roaring flame. It occurs when the air hole is fully open and allows for more oxygen to mix with the gas, creating a hotter and louder flame. Adjusting the air hole can help control the flame temperature and intensity.
The flame will be blue when the hole is fully open on a Bunsen burner. This is because the complete combustion of the gas produces a hotter flame with a blue color.
Air hole fully open gives a 'roaring blue flame'
The air hole should be fully open to ensure a safety flame. The air hole allows for proper ventilation and prevents the flame from becoming too large or unstable.
With the air hole fully open, the flame will be fierce, but I doubt if it can be said to be dangerous. Simply close the air hole a little.
A Bunsen burner flame with the air hole half open is typically called a "luminous flame." It appears yellow and produces soot due to incomplete combustion, indicating a fuel-rich environment. Adjusting the air hole allows for better control of the flame temperature and combustion efficiency.
Oxygen
Yes, to achieve a safety flame with a Bunsen burner, you should turn the air hole fully closed. This creates a yellow, luminous flame known as the safety flame, which is cooler and more visible. When you’re ready to use the burner for experiments, you can then gradually open the air hole to adjust to a blue, hotter flame for optimal performance.
A Bunsen flame is hottest when the air hole is open. When the air hole is open, more oxygen can mix with the gas, resulting in a hotter and more efficient flame. Closing the air hole restricts the amount of oxygen, leading to a cooler flame.
To get a roaring (blue) flame you simply turn the sleeve on the Bunsen burner's chimney to completely open the air hole under it. The new blue flame will be hard to see so close the air hole afterwards to make a visible flame.
The four(4) flame types of Bunsen burner is depending on flow through the throat holes (holes on the side of the Bunsen burner -- not to be confused with the needle valve for gas flow adjustment). 1) air hole closed (Safety flame used for when not in use or lighting). 2) air hole slightly open. 3) air hole half open. 4) air hole almost fully open (this is the roaring blue flame).
When the air hole is half open, the flame is called a "medium" or "moderate" flame. This means it is not burning too high or too low and is at an optimal level for cooking. Adjusting the air hole can help control the intensity of the flame.