Have you ever wondered how plants “breathe”? Even though they don’t have lungs like we do, plants need to take in gases from the air and release others to stay alive. The key to this amazing process lies in tiny openings on their leaves called stomata. These little “doors” open and close to let carbon dioxide in, oxygen out, and water vapor escape. Carbon dioxide moves in, oxygen moves out, and the flow of water vapor must be controlled. Letting water vapor escape is essential because, during transpiration, the evaporating water creates a suction that pulls water from the roots through the stem. However, if a plant lets too much water vapor escape, the plant will dehydrate and die. So the stomata have a critical role in regulating the movement of water!

In this lesson, students will explore how stomata help plants balance two essential needs: getting the gases they need for photosynthesis while keeping enough water inside to survive. In this game, students will play as atmospheric gases and guard cells that control the opening and closing of stomata. Every game result will be an opportunity for students to test their understanding of how climate influences what the stomata do.

Materials:

• Basketballs (enough for half of the class

• Scoreboard visible to the whole class (home and visitor scores)

• Pool noodles (enough for half the class)

• Whistle or timer (set to 2-minute intervals)

• Minimum Number of Students Needed: This game can be played with as few as 4 players: two guard cells and two atmosphere players (one of whom is the water player). However, this game works great for large classes, especially if you have access to multiple basketball hoops in your play setting.

• Prior Knowledge: While this game could be used to introduce how stomata control gas exchange in the leaf, I think it would be better to play it after students have used microscopes to see the stomata. This game does a good job of wrapping up a lesson on stoma by testing the kids' understanding of climate and stoma activity.