Choose a difficulty level and then click the tiles (squares). Behind each tile is a molecule that plays an important role in the chemistry and composition of our atmosphere. Each type of molecule is on two tiles. Try to match them all. (Note that, in level five, you'll match the ball-and-stick representation of each molecule with the molecular formula.) After you've mastered this game, check out other UCAR Center for Science Education Games.
Click on the pictures below to learn more about the molecules in this game.