Today was the final day of the Marooned on Mars project. Final drafts of the lab reports will be due first thing on Monday. With the procedures almost finished, most groups tackled the final and perhaps deadliest of the challenges: filtering CO₂ out of the air in Mr. Watney’s living quarters.

When limewater (CaO₂H₂) mixes with carbon dioxide (CO₂), the chemicals react and turn into water (H₂O) and chalk (CaCO₃). In other words you are taking carbon dioxide, a gas that is poisonous in large quantities, and turning it into two harmless chemicals. Once the students discovered this reaction, they went ahead and used pumps, straws, and syringes to try to filter the air in the room through the limewater.

And with that, the last of Mr. Watney’s goals was completed. Who knew? You can purify water, make oxygen, remove carbon dioxide, and grow food, all using chemical reactions!

December 2-4 – Marooned on Mars (pg318)