Easy and Fun Color Science Project
By Anne Marie Helmenstine, Ph.D., About.com Guide
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Colored Flower Materials
- fresh flowers, preferably white - don't use wilted flowers since they might not be able to absorb water well. Good choices include daisies and carnations.
- food coloring
- warm water
Make Colored Flowers
- Trim the stems of your flowers so they aren't excessively long.
- Make a slanted cut at the base of the stem under water. The cut is slanted so that the stem won't sit flat on the bottom of the container. A flat cut can prevent the flower from taking in water. Make the cut underwater to prevent air bubbles from forming in the tiny tubes at base of the stem, which would prevent water/color from being drawn up.
- Add food coloring to a glass. You're looking at about 20-30 drops of food coloring per half cup of warm water. Warm water will be taken more readily than cold water.
- Set the damp stem of the flower in the colored water. The petals should become colored after a few hours. It may take as long as 24 hours, however, depending on the flower.
- You can set the colored flowers in plain water or flower preservative, but they will continue to drink water, changing the pattern of the color over time.
Getting Fancy
You can slit the stem up the middle and put each side in a different color to get bi-colored flowers. What do you think you will get if you put half of the stem in blue dye and half in yellow dye? What do you think will happen if you take a colored flower and put its stem in dye of a different color?
How It Works
A few different processes are involved in plant 'drinking' or transpiration. As water evaporates from flowers and leaves, the attractive force between water molecules called cohesion pulls more water along. Water is pulled up through tiny tubes (xylem) that run up a plant's stem. Although gravity might want to pull the water back down toward the ground, water sticks to itself and these tubes. This capillary action keeps water in the xylem in much the same way as water stays in a straw when you suck water through it, except evaporation and biochemical reactions provide the initial upward pull.
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