Observing Water Drops
Pupils observe the behaviour of water on different plant leaves to learn about hydrophilic and hydrophobic surfaces.
Age Group: 9-12 years
Duration: 45 minutes
Biomimicry Connection:
An important part of biomimicry education is the observation of natural organisms. Do the leaves of plants behave the same way when they get wet with water? If some surfaces are water-repellent, could we be inspired to make materials for clothing or shoes that stay dry in the rain?
Activity Details:
Tools and Materials
- Digital camera (one per group of pupils)
- Projection equipment, internet connection (needed to download photos from pupils in order to project them)
Preparation
- The best time for this activity is just after rain, or even in the rain if you have waterproof clothing. Pupils should have good footwear and wet weather clothing
Description
- Divide pupils in to groups, and ensure each have at least one digital camera between them. Take a walk outside in the school garden or in the nearby natural area in the rain or shortly after the rain. Alternatively, you can use a water sprinkler to wet specific plants you are interested to observe.
- Ask groups to find different surfaces in nature (leaves, stems, flowers, stumps, trunks, etc.) that have been/are exposed to rain. Are all those surfaces wet? Or did you also find surfaces that look dry? Do you see large drops of water ‘standing’ on some surfaces? Take pictures of the parts of the plants (or other surfaces) that are visibly wet and those that look dry. Allow 10-15 minutes for this task.
- Return to the classroom and upload the photos to the computer to project them. Discuss what pupils observed. Is everything in nature wet even shortly after rain? Why do some surfaces appear dry? Do you have your own experience of which surfaces water runs off easily and which water sticks to? Why do you think this happens?
- Explain that pupils might have observed that the surfaces on some plants are able to ‘ball-up’ water into droplets so they run off quickly (see Lotus Effect exemplar to learn more). Could we use water-repellent surfaces to make our lives easier? Or avoid unnecessary toxic chemicals? Or save money? Where? For more on applications, see the Lotus Effect exemplar.