Test both conditions
Water alone and oxygen alone do not advance rust in this model.
Rust Watch
Compare iron corrosion with water and oxygen present or absent.
Grades 3–5 · Chemistry
Your goal
Expose iron to both water and oxygen for 1 model day. Observe rust stage 1.
Reduced motion is on. The controls still update the scene.
Model day 0. Rust stage 0 of 6. Both required conditions are absent.
Rust stages are qualitative illustrations, not predicted amounts or real corrosion times. Water and oxygen are replenished when present; their consumption is not calculated. Real corrosion also depends on salt, temperature, coatings and the iron surface. Rust contains matter from oxygen and water as well as iron.
Related resources
Related simulations
Learn with Rust Watch
Choose whether water and oxygen are available to an iron nail, then advance one model day at a time. Rust Watch lets elementary students compare conditions before drawing a conclusion about corrosion. The nail gains visible rust marks only when both required conditions are present. Changing a condition starts a fresh nail, making comparisons easier to explain. Guided goals include producing different rust stages and keeping iron unchanged under protective conditions. The stage numbers describe a qualitative classroom model rather than predicting how quickly a real object will rust.
What to look for
Compare fresh nails
Changing either condition resets time and the iron surface.
Explain protection
Removing a needed condition can prevent the modeled corrosion.
For teachers and curious learners
Use observations to explain why rust needs both water and oxygen. Ask students to predict what will happen, change one setting, and explain what they observe. Learn gives a starting point. Practice and Challenge offer new goals with the same scene.
Qualitative stages advance only when both water and oxygen are replenished. Model days are not real corrosion times. Temperature, salts, coatings, reactant consumption and changing iron mass are not calculated.