What method can show that blue Bunsen flame is hotter than yellow Bunsen flame?

To measure the time taken to boil a beaker of water of same mass;
put a wooden splint into the flame, and to measure the time taken for the splint to char / ignite;
place a thermometer wrapped with black paper next to the flame (but not too close), and measure the temperature rise due to absorption of IR radiation; etc.

用你的手指