Science
24 Aug 08
24 Aug 08
1 edit
As a new science teacher I had to do some demonstrations. Here's one.
I had a metal pan. In it I placed a piece of paper. I soaked the paper in a liquid, dumped out the excess, then lit the paper on fire. A couple seconds later I quickly extinguished the fire, and showed that the paper was completely undamaged. No charred bits at all.
Explain!
24 Aug 08
Originally posted by AThousandYoungYou were drinking heavily before the demonstration.
As a new science teacher I had to do some demonstrations. Here's one.
I had a metal pan. In it I placed a piece of paper. I soaked the paper in a liquid, dumped out the excess, then lit the paper on fire. A couple seconds later I quickly extinguished the fire, and showed that the paper was completely undamaged. No charred bits at all.
Explain!
24 Aug 08
Originally posted by AThousandYoungYou stood behind your table and because the class was far enough from you, you could fool them into believing that it really was paper. It was actually a painted aluminum plate which you soaked in fuel.
As a new science teacher I had to do some demonstrations. Here's one.
I had a metal pan. In it I placed a piece of paper. I soaked the paper in a liquid, dumped out the excess, then lit the paper on fire. A couple seconds later I quickly extinguished the fire, and showed that the paper was completely undamaged. No charred bits at all.
Explain!
And of course it wouldn't have worked, if you hadn't soaked it in fuel. Aluminum doesn't burn that easily. Dooh!
25 Aug 08
Originally posted by AThousandYoungI think you soaked the paper in water previous to the experiment, then put it in the pan with isopropanol until the paper had just a thin film of isopropanol on it.
As a new science teacher I had to do some demonstrations. Here's one.
I had a metal pan. In it I placed a piece of paper. I soaked the paper in a liquid, dumped out the excess, then lit the paper on fire. A couple seconds later I quickly extinguished the fire, and showed that the paper was completely undamaged. No charred bits at all.
Explain!
The paper would still be soaked with water and so would not burn but the isopropanol would burn.
?
🙂
25 Aug 08
Originally posted by mlpriorYou got the general idea.
I think you soaked the paper in water previous to the experiment, then put it in the pan with isopropanol until the paper had just a thin film of isopropanol on it.
The paper would still be soaked with water and so would not burn but the isopropanol would burn.
?
🙂
25 Aug 08
Solids don't burn. They vaporize first, then the vapors (gases) burn.
The liquid vaporizes before the solid (paper).
Only the liquid was burning, even though it looked as though the paper was burning.
The paper was a catalyst (a wick, as on a candle).
What kind of a science teacher does a cool demonstration and doesn't explain what the point was? Or, was that your assignment, to come up with the explanation? Did we help you cheat?
25 Aug 08
4 edits
Originally posted by coquetteFirst of all, I didn't do this one because it made me uncomfortable (open flame 😕) and I only had 20 minutes. It was just one of a bag of tricks and I didn't have time for it. I did an oil and water demonstration (homemade lava lamp), a salt and soda demonstration, and vinegar and baking soda. I had more planned but I only had 20 mins and I didn't bring my lighter that day anyway.
Solids don't burn. They vaporize first, then the vapors (gases) burn.
The liquid vaporizes before the solid (paper).
Only the liquid was burning, even though it looked as though the paper was burning.
The paper was a catalyst (a wick, as on a candle).
What kind of a science teacher does a cool demonstration and doesn't explain what the point was? Or, was that your assignment, to come up with the explanation? Did we help you cheat?
If I had done it, I would have explained it...after I asked my students to try to explain it to me!
Also unused were the "put out the candle with a glass" and a "relight the candle by igniting the smoke" demos, the second of which I still haven't even tried once.
It was a demo for orientation, that's all. The students didn't need to take notes or anything.