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Krampf #482 Burning Steel
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KRA-@aol.com
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Apr 10, 2007 13:40 PDT
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New Science Experiment Video
Steam Powered Can Crushing
The video is online on at:
http://www.krampf.com/experiment_vid.html
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Robert Krampf's Experiment of the Week: - #482 Burning Steel
Greetings from Ft. Lauderdale, Florida. I am back on the road, doing school
programs for Florida Power and Light. It is going to be a busy week. Omar
and I are hoping to tape more experiment videos, as well as getting the FCAT
Science videos online.
We still have copies of the FCAT Science DVD at the special Experiment of the
Week price of $14.95. You can find information and sample video at:
http://www.krampf.com/DVDspecial.html
This week's experiment is a continuation of last week's posting. We saw
that when steel combined with oxygen to form rust, it gave off heat. This week,
we will speed up the process a bit.
*WARNING* This experiment involves the use of fire. Burning steel is VERY
hot, and can easily set fire to other materials. Be safe, and be sure that
there is an adult with you to help.
To try this, you will need:
steel wool
pliers
matches or a lighter
a bowl of water
Last week, we saw that as steel wool combined with oxygen to form rust, it
gave off heat. What would happen if we speeded up the process? To do that,
separate a strand of steel wool. Hold one end of the strand in the pliers,
and bring the other end into a flame. Watch what happens. When you are
finished, dip the strand into the bowl of water to cool it.
The steel burns, giving off quite a bit of heat in the process, but it does
not burn for long. Notice that the steel does not burn up. The strand that
is left behind does not look like rust, but it is now made up of iron oxide.
Understanding the Science
How can steel burn? Well, usually it doesn't. To understand why the steel
wool burns, think about starting a campfire. What would happen if you held
a match under a large log? Would that set the log on fire? No. The match
does not give off enough heat energy to get the wood hot enough to burn.
But, what would happen if you held the match under a small twig? The smaller
piece of wood catches fire easily.
The same idea applies to the steel wool, but there is more than just heat at
work. Even with a tremendous amount of heat, steel usually does not burn.
The other difference is the amount of oxygen available. In a large piece of
steel, only the surface is in contact with oxygen. Most of the steel in
inside, where the oxygen cannot reach. With the thin strand of steel wool, all
the steel is near the surface, and near the oxygen. That availability of
oxygen allows the steel to burn.
So we see that when steel combines with oxygen, either slowly or quickly, it
always gives off energy in the form of heat. Even more interesting is that
if we measure the energy given off by both rusting and combustion, we will see
that we get the same amount of energy from each. The speed of the reaction
is different, but the total amount of energy is the same.
You may also find it interesting that after the steel burns, it weighs more
that it did originally. When wood, paper, etc. burn, much of their carbon
combines with oxygen to form carbon dioxide, which mixes with the air. For those
substances, the remains after burning will weigh quite a bit less than the
original material. With iron or steel, all the original material stays, as
well as the oxygen that it bonded with. The fact that metals gain weight when
they burn played an important role in the discovery of oxygen's role in the
burning process.
Have a wonder-filled week!
Robert Krampf
Robert Krampf's Science Education Company
www.krampf.com
Who is Robert Krampf?
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