Question

multiple - choice question
what part of the burner controls the flame height?
the gas valve - located at the bottom of the bunsen burner
the barrel - the part of the burner where the flame comes out of

Explanation:

The gas valve controls the amount of gas flowing into the Bunsen burner. More gas leads to a taller flame and less gas leads to a shorter flame. It is located at the bottom of the Bunsen burner. The barrel is just the exit - point for the gas - air mixture to burn, not the controlling factor for flame height.

Answer:

The gas valve - located at the bottom of the Bunsen burner