3rd graders learnt that plants transpire. That they lose water to the heat from the sun through stomata. To investigate this further, they trooped to the school garden, chose two lush plants, one exposed to sunlight and another in the shade and tied a plastic cover around a stem of both the plants with twine and came back the next morning. They were awed to see that both the covers had water droplets in them. More in the one exposed to sunlight and less in the one under shade.