Today at the Greensboro Science Center, we are going to be changing the color of flower petals! Not only will this experiment yield beautiful, one of a kind flowers, but it will also help us witness how quickly (or slowly!) water moves through a flower.
For this experiment you will need:
- Food coloring
- Small reusable cups or jars
- White flowers ( we used carnations since they are cheap, and available at most grocery stores. Feel free to expirement with other white flowers.)
- Scissors/ knife
- Adult supervision
- Choose what color you would like to turn your flowers, and add that color to a glass of water. Don’t be afraid to get creative with your colors by mixing two or more colors in the same jar. Be sure and use a TON of food coloring- the deeper the color of the water- the more vibrant the petal color will be (we used about 30-40 drops of each, but you can experiment with the amounts if you wish).
- Clip at least one inch from the bottom of your carnation stems, and remove any leaves that will be underwater.Make sure to cut your stems at an angle, this makes it easier for your flowers to drink the water!
- Place your clipped flowers into the colored water of your choosing, you can leave one flower in plain, uncolored water if you would like to have a “control” flower. (All true science experiments should have a control.)
- Over the next few hours and days, you will see a change in the petal color.
- If you want to make a multi-colored flower, you can cut the stem in half, and place both halves of the stems in different colored water, what do you think will happen?
Most plants “drink” water from the ground through their roots. The water travels up the stem of the plant into the leaves and flowers where it makes food and helps keep the plant rigid. When a flower is cut off the plant, it no longer has its roots but the stem of the flower still “drinks” up the water and provides it to the leaves and flowers. How does this happen?
Two things are needed to move water through plants- Transpiration and cohesion. Since water evaporates from leaves, buds, and petals, transpiration pulls water up the stem of the plant. This process is similar to that of sucking on a straw. Water that evaporates from the leaves pulls other water behind it in order to fill the space left by the evaporating water, but instead of your mouth providing the suction (like it would with a straw) the movement is due to water evaporation. This process happens because water sticks to itself ( which is called cohesion) and because the tubes in the plant stem are very small, and located in a part of the flower called the xylem.
You may want to set up an experiment that tests the transpiration rate of the flowers by placing your plant-coloring set-up in different areas such as sunny and dark, or dry and humid, and see which flower end up with the most color!
Don’t forget to show us your results by tagging us in your photos on social media using the hashtag #gscscience !