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Krampf #480 Heating a Balloon
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KRA-@aol.com
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Mar 27, 2007 18:50 PST
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Robert Krampf's Experiment of the Week
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Greetings from our home in Jacksonville. Thanks to everyone who watched the
first two experiment videos, and especially thanks for all the wonderful
feedback. This week I am focusing on producing more experiment videos, as well
as playing with stereophotography, helping Nancy with the gardening, and
preparing to put some of my photo galleries back on the website.
Quite a few of you have asked about buying a copy of my first FCAT science
DVD. In the next few weeks, we plan to make those videos available on the
website, but we are also making arrangements so that you can purchase an actual
FCAT Science DVD, if you want to have your very own copy. By next week I
should have more information.
This Weeks Experiment - Heating a Balloon
Taken from the original version of experiment #13, written May 15, 1997.
You can see the video version of this experiment at:
http://www.krampf.com/experiment_vid.html
*WARNING* This experiment uses fire. Be safe, use common sense, and be
sure there is an adult in the room, so you have someone to blame if something
goes wrong.
This is a variation of an old, Victorian parlor trick, but even after more
than 100 years, it is still just as amazing. In Victorian times, the
experiment was done by folding a calling card (much like a modern business card) into a
square container. When the paper container was filled with water, it could
be held over a candle to boil the water without the paper catching fire.
For this modern version, you will need:
a candle
matches or a lighter
several balloons
water
Blow up one of the balloons and tie it off. Light the candle. Now, what
do you think would happen if you held the balloon in the candle flame? Lets
try it and see. Carefully, hold the balloon just at the top of the candle
flame. BANG! Just as you probably predicted, the balloon pops and it blows
out the candle.
Now, lets try that again, but this time with a twist. Instead of filling
the balloon with air, lets make it a little more fun. Lets try the experiment
with a water balloon! Carefully stretch the mouth of the balloon over a
water faucet and slowly fill the balloon with water. Then blow in a little air
and tie it off.
At this point, work over a sink or outside, just in case things don't work as
they should. Once again, light the candle, and hold the balloon over the
candle, just at the top of the flame. What happens? You probably expected
the balloon to pop, getting you wet. Instead, the bottom of the balloon turned
black, but it did not pop. Why?
Understanding the Science
Water is very good at soaking up heat. Because the balloon is very thin,
heat energy passes through it quickly heating the water on the inside. As the
water near the flame starts to get hot, it rises, letting cooler water take
its place to soak up more heat. This process lets the water balloon absorb a
tremendous amount of heat without popping.
The black stuff on the balloon is the element carbon. It did not come from
the balloon. Instead, it was deposited by the candle flame. The balloon
has not been burned or damaged.
The idea of absorbing heat to control it is a very useful idea indeed.
Firefighters use it to protect themselves while they are fighting fires. The
radiator in your car absorbs heat from the engine to keep it from overheating.
Heat sinks in computers absorb heat to protect delicate circuits. The idea
even applies to ice cream, which absorbs the heat from hot fudge sauce, cooling
it enough so you can eat it without burning your mouth. That sounds like an
experiment worth trying.
Have a wonder-filled week!
Robert Krampf
Robert Krampf's Science Education Company
www.krampf.com
Who is Robert Krampf?
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