Experiment: Saltwater rust
Thursday, November 8, 2012
Using a few materials from around the house, you can see the effect that saltwater rust will have on New York City's subway system after superstorm Sandy.
* Two transparent cups
* Warm water
* Two white plates
* Two steel-wool pads
STEP 1: Fill each cup 3/4 of the way with warm water. Mix three tablespoons of salt into one of the cups of warm water. Label the cup "saltwater."
STEP 2: Place one of the steel-wool pads into the cup of saltwater and one of the steel-wool pads into the cup of water without salt.
STEP 3: After five minutes place the steel-wool pad in the saltwater onto a white plate and the steel-wool pad in the water without the salt onto the other white plate. Wait a few days and observe.
After a few days the steel-wool pad in the saltwater will have more rust. The salt makes the water a better conductor. That means more electricity can pass through, which produces more oxygen. The more oxygen present the more rust forms.
Jason Lindsey is a science outreach educator with Hooked on Science. Check out his website www.hookedonscience.org for webcasts and experiments.