Green Blobs from Steel Wool

    Kids, our purpose in this experiment is to make a green, jelly-like blob from mixing two liquids. One liquid is made by dissolving steel wool. You will need vinegar, steel wool (pure - no soap), household ammonia, and 2 small baby food jars.

    Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

    Fill one jar half way with steel wool. Add enough vinegar to cover the steel wool and close the jar. Write IRON ACETATE on the side of the glass. You will have to be patient and let this jar stand undisturbed for five days. Then pour one tablespoon of your liquid Iron Acetate into the second jar. Add one tablespoon of household ammonia and stir. What happens? A dark green, glutinous material forms immediately.

    The iron in the steel wool combines with the vinegar (weak acetic acid) to produce iron acetate. The active component of household ammonia is a compound called ammonium hydroxide. A chemical reaction occurs as soon as these two liquids combine. So, ammonium hydroxide + iron acetate make ammonium acetate + iron hydroxide. Note that what happens is really just an exchange of materials. The same ingredients of ammonium, iron, hydroxide, and acetate are present, but their recombination produces a totally different product. In fact, two liquids (solutions of iron acetate and ammonium hydroxide) have reacted to form a new phase - your gel!

    (Safety concerns are typical: no eating, wash any skin contact with water, and dispose of materials down the sink with water.)


    Kathleen Carrado Gregar, PhD, Argonne National Labs 
    [email protected]
    October 1994


    Reference: Janice VanCleave's "Chemistry for Every Kid" 1989, p.102.