How Can You Write A Conclusion About Rusting On Iron In Air?

To write a conclusion you usually have conducted an experiment that involves the factors involved in producing whatever changes are observed

in this case the iron (nail) will be used in a similar way in each process

rusting suggests water being involved ,so the nail has to be wet and dry to make a justifiable conclusion ;  also if you boil water this removes the air from the water and a covering of oil over the boiled water stops the air from getting back into the container ( test -tube ?)

4 test tubes could be set up 1. Nail in air only, stoppered   NO RUSTING2.nail in water only  stoppered  RUSTING3.nail in boiled water with oil covering   NO RUSTING4.nail in boiled water, uncovered   RUSTING

nail with moisture and air produces rusting ;