One of my goals with these science videos is to provide support to the homeschool community. After years of writing the Experiment of the Week, and presenting science shows for homeschool groups, I have been impressed with how strongly homeschool families are involved with hands-on science. I have also seen the need for a science curriculum that fulfills their educational needs. Starting with these videos, I hope to offer the homeschool community some of the science education support that they need, as well as a fun way to get students involved with scientific discovery.
I also try to use activities that involve common items. Most homeschoolers don't have access to test tubes, flasks, chemicals, microscopes and other scientific equipment. In the future, I hope to be able to guide them to inexpensive sources for science equipment to enrich their science curriculum.
This week's experiment combines the science of chemistry with the beauty of flowers. We will alter that beauty by causing the flowers to change colors.
To try this, you will need:
- a tall container with a large opening and a tight fitting lid. A clear container is more fun, but any will do.
- ammonia
- Red, blue or purple flowers
- string
- tape
After gathering the materials, you need to gather some flowers. Important Note: ASK BEFORE YOU PICK THE FLOWERS! I know from experience that gardeners get very unhappy if you pick the wrong flowers. Try to get flowers of different colors. I have found that purple, blue, yellow and red flowers usually work the best, but try a variety. Some may surprise you by dramatic changes, and others may not change at all.
Arrange the flowers so you can see the different colors easily. Use some string or thread to tie them together. Pour about half in inch of ammonia into the tall container. Then use the string to suspend the flowers, so that they hang just above the surface of the ammonia. Tape the string in place and put the lid on the container.
Now, all you have to do is wait about 10 to 15 minutes, just enough time for a bowl of ice cream. Check the flowers periodically, and you should be able to see the change happening. After a few minutes, you should notice some dramatic changes in the color of the flowers.
Understanding the Science
Purple flowers often turn green. I have read descriptions of this experiment which claim that this shows that flowers contain chlorophyll, but actually, the green color is due to a chemical change in the pigment of the flower. The flowers change because their color is produced by chemicals called anthocyanins. These chemicals change color in the presence of acids and bases. Chemicals that do this are called pH indicators.
Red flowers often change blue. Yellow flowers sometimes change to orange or red. Experiment with several kinds of flowers, to see what color changes you get. This is a fun way to make unusual flower arrangements.
In some plants, the reaction of these pigments to acidity can actually tell you about the soil. Hydrangeas can tell you about your soil. Acid soil will give you pink flowers. Basic soil will give you blue flowers. Your local garden shop will have soil pH test kits to tell you about your soil, and by adding chemicals like lime and sulfur, you can adjust your soil to get the color hydrangeas that you want.
Have a wonder-filled week.
