Dying flower is a fun and easy experiment. Photo: activity-box.com
Here’s a simple summer rainy day project for bored children. Teach them how to dye flowers!
Then add a bit of a botany lesson at the end.
Gather the Materials
All you need are white or pale-colored flowers fresh from the flower garden, a few tall glasses, water, scissors, a stirring spoon and some food coloring (food coloring is nontoxic to plants).
Among the flowers you could choose from are daisies, cosmos, tulips, chrysanthemums, lilies and roses, but really, almost any flower will work.
They should be white or a pale color, though; dyes won’t show up as well on darker flowers. And avoid fading flowers: fresh flowers just opening are best.
Step by Step
- Harvest fresh flowers from the garden.
- Strip the flowers of their lower leaves (any that will be underwater).
- Fill the glasses three-quarters full with warm water.
- Add about 20 to 30 drops of food color (your choice of color) to the water and stir.
- Insert the flower’s stem into the glass, then recut the stem underwater. (Recutting underwater ensures colored water moves into the cut stem, not air bubbles.)
- Remove the bit of floating stem.
- Repeat with other colors. You can mix food colorings to create your own original hues.
- Come back in a few hours to see if there is any difference. Then again yet a few hours later. With some flowers, the full color change can take nearly 24 hours.
By the end of the project, you’ll have turned the white flowers to various shades. You can use them to create a lovely bouquet, perhaps a gift for someone’s birthday!
How Does This Work?
How much you explain to the children will depend on their age … and their scientific bent, but here goes for a rough explanation.
Flowers lose water through transpiration: their open pores allow water to evaporate (disappear into the air). To compensate, they absorb more.
Colored water from the glass will move up the stem through tiny tubes called xylem. It moves up the xylem due to cohesion: water molecules attract each other and move it up the stem, carrying dye to the blooms. This is called capillary action. It’s much like sucking on a straw will pull water from a glass into your mouth, except it’s the evaporation from the flower above that does the pulling.
The fresh water evaporates from the flower, but the dye doesn’t, leaving the flower color changed.
Will Flowers Also Absorb Dye Through Their Roots?
That’s a question the children might ask you.
This could also be another experiment to try, but it’s more complicated: you’d need potted plants bearing white or pale blooms. Plus, it’s easy for overeager young waterers to drown the plant with repeated doses of colored water. And rotting plants may not be your ultimate goal.
That’s why you might just want to explain the situation to the children rather than demonstrating it.
Here’s what you can say:
Plants usually absorb water and nutrients through their roots, but roots are also designed to be filters in order to keep out toxins. They act as a defensive barrier and only absorb what plants need in order to grow. That means that little if any coloring (even though it isn’t toxic) will get through and so no color change will occur in the flowers. And all that food coloring would just go to waste!