Transpiration is the process by which plants release water vapor from their leaves into the atmosphere. An experiment was conducted to compare the transpiration rates of two different plants by placing them in sealed bags and measuring humidity over time. The results showed that humidity inside the bag with plant B decreased more over the hour-long experiment, indicating that plant B had a higher transpiration rate. Transpiration cools plants by using energy from the sun to evaporate water from the leaves into the air, similar to how human sweating cools our bodies.