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 measuring humidity levels inside bags enclosing branches of each plant over 30 minutes. The results showed that humidity inside the bag of plant B decreased more over time than plant A, indicating plant B had a higher transpiration rate. Transpiration cools plants by evaporative cooling, analogous to how sweating cools humans.