Original question: What's the best thing you've heard your teacher say?
The first day I walked into my 10th grade chemistry class, the lights were off. The teacher was waiting at the front of the room, holding a small candle in front of him. The candle's tiny flame was the only source of light in the room.
The class murmured a bit, confused and excited. Once we’d all quieted down, the teacher said, “Tell me some of the observations you can make about this candle."
We paused for a moment. That seemed a little too easy for chemistry class.
"But keep in mind," the teacher added, "that observations are the things you observe empirically. Inferences are the things you conclude… and inferences can be wrong.”
We stared at him, wary now.
At last, someone piped up, “Um...The flame is yellow?”
“The flame gives off heat."
"The wick is burning."
"The wax is cylindrical!"
The teacher raised his eyebrows at that one. "Are you sure?"
We stared harder at the candle, not sure how to respond to that. It definitely looked cylindrical.
The teacher shrugged. Then he put the candle into his mouth and started chewing.
The class stared at him.
At this point I was wondering if I ought to call the emergency room or something, but the teacher just kept chewing as though nothing was wrong. Eventually, he swallowed, shrugged again, and said, “Actually tastes okay.”
As it turns out, the so-called “candle” wasn't made out of wax at all. It was actually just a slice of banana, with an almond slice for the wick.
The student’s “wax” statement had actually been an inference.
After explaining this to us, the teacher turned on the lights and said, "If there's one thing I want you to learn in this class, it's the first rule of scientific thinking: Never assume that your mind can’t lie to you."
And that's the story of how my 10th-grade chemistry teacher swallowed a candle to teach us the first principle of scientific thinking. Here's to you, Mr. Miller.
EDIT: A lot of readers seem to be confused about how the banana candle could be lit like a normal candle. The answer's pretty simple - you just light the sliver of almond on fire! If you want to know more, you can google "edible candle." Quora User asked about this in the comments and then made one himself, and the result was pretty cool:
Mr. Miller's candle looked a lot like Evan's, but without the awesome plate.