Lab Introduction
As you learned earlier, after photosynthesis began on Earth, oxygen levels began to increase (because photosynthesis gives off oxygen). But at first, this oxygen did not accumulate in the atmosphere because it was removed from the air by a reaction with iron in the oceans. In other words, iron in the oceans removed the oxygen from the air. Once all the iron in the oceans reacted, oxygen was then free to begin accumulating in the atmosphere.
This activity will help you visualize how iron can remove oxygen from the air.