Purpose to observe the effect that protective coatings have on the rusting of steel wool.
Things Required:
1 steel wool soap pad
Scissors
Plate
1 sheet paper toweling
1/2 cup of vinegar pencil
Directions:
Cut the steel wool pad into four equal parts. Run warm tap water over two of the pieces to remove as much of the soap as possible. Place one piece with soap and one piece without soap in the vinegar. Mark the paper towel into four equal parts. Number each section. Lie the paper towel over a plate. Remove the pieces from the vinegar and squeeze out as much liquid as possible. Place the steel wool pieces in these indicated sections: Section 1: Piece with no soap and soaked in vinegar. Section 2: Piece with soap and soaked in vinegar. Section 3: Piece with no soap, but wet with water. Section 4: Dry piece with soap. This is the control.
Observe the steel wool pieces every 10 minutes for one hour and then allow them to stand for 24 hours.
This Is What Happens:
The piece with no soap that has been soaked in vinegar shows the signs of rusting after 10 minutes. It takes up to one hour for the piece with soap that was soaked in vinegar to rust. After 24 hours the vinegar-soaked pieces have equally rusted and the piece wet with water and containing no soap shows only slight rusting. No change is seen in the control.
Note: A control is any material that is not changed at the start of the experiment.
Science Behind It:
Steel wool contains iron which rusts by combining with oxygen in the air. Soap helps to prevent air from touching the iron. The vinegar cleans off any additional coating on the steel wool, allowing iron and oxygen to combine. The iron oxide that is formed is reddish-brown in colour. One usually thinks of rust as being this colour, but other colours are formed when different metals rust by combining with oxygen.
