Cambridge Secondary (7-9). Stage 9. Science. Learner's Book - Unit 1: Photosynthesis and the carbon cycle - Question 27

Which surface of a leaf has most stomata? Work with a partner for this activity. Put some warm (not hot) water into a beaker or glass. Take a fresh leaf, and push it down under the water. Can you see any bubbles coming out of the leaf? Which surface of the leaf do most of the bubbles come from?