Originally Posted by 01101001

It surely wasn't my intended meaning. Next time, should it come up, I'll try to remember to use missed, as less open to an unfortunate misinterpretation. I meant to allow for skipping of the demo by virtue of necessity, like illness. That I recall, I never skipped a class for an illegitimate reason, so it's not the primary connotation of the word for me.

It was a struggle for me to understand the question, knowing that this is a common demonstration. I wondered how someone could have seen that demo and still asked that question. Thinking, on those lines, voicing them, I suspected it had been missed (right word?) and proceeded to find similar on the Net. I thought it added something, it helped -- until m1omg came back with a clarification that confused me further.

I saw the oxygen-concentration demos at a young age, grade school, when fire makes a great teaching tool. Is it college material now? Yikes!