Question

when heating a beaker, where should the burner flame be located for maximum heating?

Answer 1

middle of the beaker I assume.

Answer 2

Under the middle of the beaker.

Answer 3

Under the beaker with the tip of the inner blue cone of the burner just touching. However, I never like to heat a beaker directly (unless it's made of Vycor). I prefer to place the beaker on top of a wire gauze and heat the wire gauze. Beakers made of Pyrex have been known to crack if heated directly.