We want your opinion!
Please click here to take our survey.
Teachers who complete and submit the survey will be entered in a drawing to win:
Drawings will announced in December 2016 and May 2017 by NorthWestern Energy.
Limited one gift card per winning entry. Teachers may only enter once per semester.
No purchase required.
How rapidly does a plant make starch?
Tincture of iodine
Graduated cylinder (A test tube marked in milliliters [ml]-- borrow from a high school chemistry lab)
Do this first:
1. Place the geranium in a dark closet for 2- 3 days. The leaves will begin to turn white.
2. Make an iodine solution by adding 5-ml iodine to 45-ml water.
3. Test the potato of starch. Place a few drops of iodine solution on the potato. If it turns blue it has starch in it!
4. Now test a white leaf from the geranium by crushing it in a small amount of water. What happens? Test the sugar. What happens?
5. Remove several leaves from the geranium. Cover in places with black paper strips and place in the sun for 2 hours. How long does it take for the leaves to turn green? Now test the leaves for starch again.
What happens to the leaf under the black paper? Test it for starch too!
OTHER IDEAS TO EXPLORE:
Test different foods for starch. Do some plants have more starch than others? Where did the starch come from?
Can you trace your dinner back to the sun?
Register here for FREE bi-annual newsletters with information and ideas for your classroom
classroom teaching materials.
© 2016 Moore Syndication Inc. No reproduction without permission. All rights reserved.