Let's Set Fire to Steel

Blazing Steel

©2009 James P. Louviere

There’s a huge world of confusion about everyday physics. For example, today I’d like to show you a quick and lot-cost way of telling the difference between “heat” and “temperature.”

When I was a kid, my dad had a shop in our back yard. It was old, unpainted cypress wood, and the floor was simple dirt, mostly clay, and covered with sawdust from his table saw, as well as shavings from his woodworking lathe, this drill press, band saw, and hand planers, rasps, and so on. When he has to sharpen a hoe, shovel, or knife, he’s use an emery wheel mounted on his lathe and when he turned on the power, the bulky wheel would spin very fast, and he’s shove the metal blade against the wheel and sparks would shower down into the sawdust on the floor. I was really sure that he’d burn the place down, but then he was forty years older and I was, and was a combat veteran from WWI in Germany and France, and had about fifty years experience in his shop, where he used molten aluminum to make knife handles, “spiders” for ceiling fans, and other sand-cast materials. He had also wired our home, steamed bamboo into shape to produce all-bamboo rakes, and so on.

Eventually he won out by showing me that the yellow sparks were completely harmless by holding his bare hand in the shower of sparks, without being uncomfortable. I tried it myself, and sure enough, the sparks did not feel hot at all.

You see, “heat” is the amount of energy a piece of material has in it due to the vibration or oscillation of its subatomic particles. A very tiny piece of yellow-hot steel is so small that the heat it contains is very intense, but the sum total of the total mass is practically zero in real life terms. Compared to the “huge” amount of matter in my young hand back then, a tiny speck of hot metal could not heat up my hand at all/ my comparison, the hot water in my hot cocoa at breakfast could really hurt my lips and mouth. It was not even boiling yet, and its temperature was perhaps more than 500 degrees F lower than the temperature of a metal spark in the shop, but there was a lot more hot matter (mass) in the cup than in the tiny spark. It’s not the temperature alone that causes a fire – it’s the amount of hot matter that makes a difference.

Things to get before you start your Blazing Steel experiment:

· a newspaper

· a match (big kitchen match is preferred)

· some steel wool, preferably “fine” grade, but medium or coarse grade will do.

· Do not use a Stainless Steel Scrubbing Pad or a Brillo ^{(R )}Pad. Be careful – can slice one’s

fingers!

· Match or burning candle to use to set fire to the steel wool.

· Notebook (you should have one to record your various activities.

· Pen or pencil for recording your observations before and after the activity.

· a pair of pliers to pull the steel wool apart and to hold it while it flames.

What to do: In a well ventilated area, lay out a complete newspaper on a table, folded

across the front page in the usual manner. It should have at least twelve pages or so, or use two or more in order to get a thick folded set of papers.

Wear your safety glasses as usual, or goggles, just in case there’s an accident.

Grip the hunk of steel wool with a mitt and use pliers to pull off a nice piece about the size of your thumb, but not as “solid.” Make sure it is not matted – it can be “teased” using a pencil or pen to be sure it is fluffier and less compact than a tight wad of the material would be.

Do this so air can get between all the fibers of steel.

How light a match and hold it to the steel wool. If it starts burning brightly, drop it onto the newspaper and fold the paper quickly between the sheets.

Open the news paper. Write down what you observed. If you don’t keep records, you are playing, but you are not doing science. Science depends on accurate records. No records, no science.

Questions to answer in sentence form:

1. Was the steel able to burn?

2. Did the newspaper catch fire?

3. What happened when the blazing steel wool was dropped on the newspaper, and the newspaper was folded to squeeze the burning steel wool?

4. Hold the newspaper sheets that touched the burning steel wool up to the light.

5. Did the burning steel wool make holes in the paper it was lying on? Did the covering sheet of paper have holes burned in it?

6. If there were holes, measure their diameter and describe them. How big are they?

7. The burning point temperature of steel is about 800 degrees F. Does that sound like it should be able to start a fire?

8. Explain what is needed to set fire to a newspaper.

9. Check your answer against this on I made up: To burn newspaper, you need a supply of air and you need to have just a single piece of paper so that the paper is easy to heat up, and there’s enough hot matter to sustain the heating until the paper begins to turn into vapor. Solid paper itself does not burn until it vaporizes.

10. Which reaches a higher temperature, a burning piece of paper or a burning piece of steel?

11. Why is it true that a tub of luke warm water can have more total “heat” than a burning piece of steel wool?

12. Someone once said, “In story of the Titanic, the iceberg held more heat than the captain’s cup of hot coffee?” Is this true? (Don’t forget, ice forms at 32 deg F, or 0 deg. C. “Absolute zero” is 273 deg. colder than ice in an iceberg. So icebergs do have “heat energy.” Now what’s your answer? Why?

A brick out in the yard in the shade on a warm summer day may contain a lot more “heat” than a spark from a grinding wheel.

Can you think of any other activities you could try to see if you can show for sure that “heat” means one thing, and “temperature” means a completely different things.?

Can you recall any surprises you ever had regarding heat and temperature?

Explain.

Before you put you neat notebook away, be sure you record the date you did this activity.

What did this activity do for you? How did you “change”?