Steel Wool and 9 Volt Battery Experiment

 

We studied physics and electricity a bit last school year with Electricity and Magnetism, by Colleen Kessler from RaisingLifelongLearners.com, and Snap Circuits. So when I broke out this steel wool 9-volt battery experiment, my children understood what was happening, but couldn’t quite believe their eyes. In fact, we’ve done this experiment about 10 times in the last week. It never gets old.

Related post: Make An Electroscope

The Steel Wool 9 Volt Battery Experiment

This steel wool 9-volt battery experiment is a fun, easy way for middle and high school students to learn about electricity, physics, and chemistry. It only requires 3 materials and some adult supervision.

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Related post: Electronics Lessons For Kids

Materials

– Fine Steel Wool (We used 0000)
– 9-volt battery
– Baking pan (We used a disposable aluminum pan)

Procedure

1. Before beginning, take the following safety precautions:
   1. Put on safety glasses
   2. Tie back and long hair
   3. This should not be done near an open fire or flammable liquids
   4. Work in an area that is clean, dry, and grease-free.

2.Pull the steel wool apart into thin strips and then form a loose ball.

3. Place the steel wool in the baking pan.

4. Touch the ends of the battery to the steel wool.

What happened?

Steel wool is made mostly of iron (about 98%) and melts at 2795 ^oF (1535 ^oC). These iron threads have lots of surface area surrounded by pockets of oxygen.

When both battery terminals touch the steel wool, the electrons from the battery move rapidly through the steel wool and make a complete circuit. The electrical current heats up the wire (700 degrees) and this heat causes the iron to react with the oxygen surrounding the steel wool. This reaction creates the spark that we see and the release of heat that heats up the next iron molecules, thus causing chain reactions through the steel wool.

This reaction of iron and oxygen, also, creates a new substance, iron oxide (FeO2). Iron oxide is actually heavier than iron, making the resulting product heavier than the original steel wool.

Experiment further

Try different gauges of steel wool to see if the reaction is different.

Blow on the steel wool while it is reacting. Does it speed up or slow down the reaction? Why?

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