If you are interested in teaching your students about chemical reactions then you will want to add this one to the must-do science lessons! Burning steel wool gives you a spectacular display in a combustion reaction. All you need is some fine-grade steel wool, a 9-volt battery and safety procedures, and a pan.
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Safety First Burning Steel Wool
Pull back your hair, wear safety goggles, remove flammable items from close by and wear gloves that will protect you from heat.
STEPS for Burning Steel Wool
Step One: pull the steel wool apart so that it has some air pockets.
Step Two: push the steel wool into a loosely packed ball.
Step Three: Place the steel wool ball into a baking pan.
Step Five: Using a 9-volt battery, touch both ends to the steel wool.
Why does the steel wool ignite?
Steel wool is made mostly of iron (about 98%). Steel wool is made of lots of thin strands. These iron threads have a lot 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 creating a complete circuit. The electrical current heats up the wire (700 degrees). The 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. The very bright light is because of the extreme heat. This chemical reaction of iron and oxygen, also, creates a new substance, iron oxide (FeO2). Iron oxide is heavier than iron, making the resulting product heavier than the original steel wool. This experiment is an example of an exothermic reaction, a chemical reaction that releases energy in the form of heat. Once the steel wool has burned, it is a greyish color and can no longer be ignited. This is proof that that the steel wool has been chemically changed into the compound iron oxide.
Burning Steel Wool is a Chemical Reaction
The chemical equation for this reaction is 2H2(g) + O2 → 2H2O(g)
I use this reaction as one of five science investigations in my unit for Middle School Science on Chemical Reactions. Students love chemistry!
Normally we do not think of iron as being flammable, this is because bulk iron doesn’t self-sustain its burning like most flammable materials. But the strands of steel wool are thin enough with enough surface area that the heat produced is self-sustaining and will continue to burn through if there is enough air present.
The reason that a block of iron or steel doesn’t burn is that it’s really hard to get the oxygen molecules close enough to the iron to react.
Compare that to highly combustible materials, like wood. Wood actually lets out combustible gases as it burns, which react immediately with oxygen.
Iron doesn’t do this. Since our atmosphere is only 20% oxygen anyway, it takes some special measures to get enough oxygen to react with iron to cause combustion.
Would you like a free sample lesson from this unit? Get your free chemical reaction lesson today!
NGSS MS-PS1-2 and Utah SEEd 8.1.3
This great Middle School Science Unit is on Chemical Reactions: Students will observe substances before and after interacting to see if a chemical reaction has occurred. In this resource, students will learn about the signs of chemical reactions, chemical equations, and types of chemical reactions while completing 5 hands-on science investigations! This resource includes a 30-page slide show on chemical reactions and their properties. This resource includes labs with clear directions, follow-up pages, an informational text article, and a multiple-choice quiz. This is a huge unit with over 90 pages and slides.
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This resource includes the following science investigations:
Combustion: Burning Steel Wool
Producing a Precipitate
Acid and Base Reaction
Chemical and Physical Reactions
Thank you for visiting! I hope you will check out this great middle school science resource.
FREE Chemical Reaction Resource