Conduct a simple time experiment to test how fast and which kinds of metals corrode. Questions might include "Can zinc (or copper or any other metal) rust?" or "Which metal rusts faster?" Set up an experiment by suspending several lengths of wire of different metals in a container of water. Make daily observations, noting changes in the wire consisting of each type of metal. After about a week, students will notice that some wires rust while others do not, proving that some metals rust faster than others.
Another simple experiment examines how salinity, or saltiness, affects the corrosion of metal. Questions might include "Does salt water cause iron/steel to rust faster?" or "Will iron rust faster by the ocean?" or "What brand of road salt causes metal to rust the fastest?" To set up an experiment, leave iron nails in jars of water, with each sample having a different amount of salt dissolved in the water. Alternatively, prepare jars of water with equal amounts of different brands of road salt dissolved, and test to see if certain brands of road salts affect metals more quickly or dramatically. This experiment works for elementary students, or allows older students to conduct brand comparisons and discuss other possible chemical effects.
A more complex experiment looks at how acids affect corrosion of iron, steel and other metals. Questions might include "Does the acidity of a solution affect the rate of corrosion?" or "Are some metals more resistant to acid-based corrosion?" Set up containers with solutions using common household acids (orange juice, vinegar, coffee, nail polish remover, etc.), then suspend wires of different materials in each acid and observe the effects over time. Using a pH testing kit, rate the acidity of each solution and compare acidity with rate of corrosion. This experiment can be used to emphasize the impact of acid rain on the environment and on buildings and cities.
An interesting project for middle or high school students examines the effect that temperature has on the corrosion of metals. Questions might include "Do metals corrode faster in warmer temperatures?" or "Does temperature affect the corrosion of all metals in the same way?" To test these questions, place wires of various metals in water or vinegar, and store the containers at various temperatures. Observe which metals rust at various temperatures, or under which temperature conditions rust occurs the fastest. This experiment allows the student to see whether heat makes metal corrode faster, and which metals are more reactive to heat. This project can be used to emphasize the importance of proper storage and care of metals, and to discuss problems manufacturing companies and industrial centers may experience.