At the beginning of summer, some paint was scratched off a student’s bicycle. The exposed metal where the bicycle was scratched had a shiny, silvery color. The student kept the bicycle outside all summer. By the end of summer, the exposed metal had changed to rust, which is dark orange in color. The student did some research to find out what happened to the metal and learned that the bicycle is made of steel, which contains mostly iron. The student conducted an investigation to learn more about the process that changed the steel into rust. The student placed equal amounts of iron filings (small pieces of iron) into beakers X, Y, and Z. At the start of the investigation, all of the filings were gray. The student added nothing else to beaker X, water to beaker Y, and table salt (NaCl) and hydrogen peroxide (H2O2) to beaker Z. The student’s observations over a two-day period are shown in the table.
