It’s easy to see how plants drink water by doing this simple science experiment: Color Changing Flowers. Learn about plant biology and create a beautiful flower rainbow the kids will love. It’s a must-try kids’ plant experiment!
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This experiment can be done with any white flower. Carnations, daisies and white roses will all yield gorgeous results.
We live next to a field with hundreds of wild white daisies growing in it. One sunny day we took a walk and picked a handful.
Once we got home we filled six small film canisters with water and then dripped about 3 drops of food coloring in each one. We made an entire rainbow: red, orange, yellow, green, blue and purple. The kids placed a few flowers in each container and then we waited to see what would happen.
Color Changing Daisies
It took a few hours for anything visual to happen. During that time, we talked about how plants drink water.
I asked the kids how very tall plants get water all the way up to their highest leaves, branches and flowers. The kids had lots of very funny and creative ideas!
I guided the discussion to lead my children to the conclusion that plants absorb water through their roots in the ground. Water moves from the roots up through the stem and into the leaves and flowers through tissue called xylem.
After a couple of hours we started to see blue-tinged petals on the flower in the blue water. Little by little, each of the other flowers changed colors, too! It was interesting to note that some of the colors, like blue and purple, were more vibrant than other colors, like orange and yellow.
We left our color changing daisies overnight to develop. The next morning we had a beautiful daisy rainbow.
How Plants Drink Water
As mentioned above, water moves through plants through the xylem. But how does water defy gravity and move upward to the very highest leaves of a tree?
The answer lies in capillary action, which is defined as the process that plants use to pull water up from the ground. There are several factors that enable capillary action to happen.
First is the force of adhesion, which is the attraction between water molecules and plant fibers.
Second is the force of cohesion, which is the attraction of one water molecule to another water molecule.
Third is transpiration. When water evaporates from the leaves, buds, and petals of a plant, more water is drawn upward to fill in the empty space. It is similar to what happens when a person sucks water through a straw.
All three of these factors combine to enable a plant to draw water from the ground and distribute it throughout the entire plant. Doing this color changing flower experiment makes it easy to see how capillary action works.
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