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Nasturtium Leaves

I'm Jasmine, during the summer I like to volunteer at the San Francisco Botanical Gardens with my friend Melinda. This summer our job was watering plants. While we were watering, Melinda and I noticed that different plants handled water in different ways. This got us thinking: Why do some leaves shed water and others don't?

What did we do?
We headed to the Exploratorium in California to learn more. We experimented with nasturtium leaves and found out they have waxy nanohairs that help them repel water. We collected various types of plants with hairy leaves for our own investigation. We looked at a nasturtium, geranium, sunflower, begonia and lamb's ear. We made a chart to compare their hairs, texture, and reaction to water. We took our findings to Stanford University where nanoscientist Marja helped explain why some plants repelled water more than others.

What did we find out?
The nasturtium and lamb's ear plants worked best when it came to repelling water, but only the nasturtium leaf passed our dunk test and never got wet! Marja explained that this was because of "nanowhiskers." The nasturtium leaf had waxy looking nanohairs that allowed the water to bead up on top of the plant and roll off without being absorbed. This idea is being copied by scientists to create fabrics that shed water and even repel stains!

What can you do?
  • Take a glass and fill it to the brim with water. How many pennies do you think you can fit in the glass before it overflows? Try it!
  • Take a walk around your neighborhood or local park and collect leaves. HINT: If you want a leaf that behaves similar to a nasturtium, try cabbage! Drop water on the leaves first and then try dunking them. How are they different?
  • Place a piece of wax paper on a table. Place 3-4 separate drops of water on the paper. Wet a toothpick with water and bring it near, but not touching, one of the drops. What happens?
  • Experiment with how water behaves on different surfaces. Place drops of water on a coffee filter, wax paper, notebook paper and plastic wrap. What different shapes do the water droplets take?
more resources

Go to the DFTV Boards, and tell us about your science investigation.
whiz quiz
If a gecko could use every one of its setae, or tiny hairs, on all four feet, how much weight could it hold and still stick to the ceiling?

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