Y10 Transpiration

Question 1

How does temperature affect the rate of transpiration?

Answer 1

As the temperature increases, the molecules have a higher kinetic energy. This allows them to travel further distances, increasing transpiration rate. It also increases the rate of diffusion. The rate of photosynthesis so more stomata open for gas exchange to take place.

Question 2

How does humidity affect transpiration?

Answer 2

Hot, dry, windy conditions increase the rate of transpiration because more water evaporates from the cells, and diffusion happens at a faster rate. Water vapour diffuses more rapidly into dry air than into humid air because the concentration gradient is steeper.

Question 3

How does air movement affect transpiration?

Answer 3

Windy air conditions increase the rate of evaporation because it makes a steep concentration gradient due to the wind moving the water molecules away. This increases the rate of diffusion, which increases the rate of evaporation. Because of the high rate of evaporation, more water molecules are used in transpiration.