Conditions for rusting

O/L Science · G.C.E. Ordinary Level · Grades 10–11

Aim

To show that iron rusts only when both water and air are present.

Apparatus

• 5 test tubes with iron nails
• Calcium chloride, oil, salt
• Boiled water and grease

Method

1. Set up 5 tubes: moist air, dry air, boiled water + oil, salt water, a greased nail.
2. Observe after 1, 3 and 7 days.
3. Record how much rust forms in a table.

Conclusion

Rusting needs both water and air. Salt speeds it up; a coat of grease or oil prevents it.