Finding Food in Plants
Day 1: Place a leaf in and jar and fill jar with @ a cup of rubbing alcohol. Put a lid on the jar and let it sit overnight. This will break down the leaf's protective coating. It will also pull out the chlorophyll, the chemical that gives the leaf its green color.
A. Dump out the alcohol and place the leaf in a shallow dish. Pour enough iodine on it so that the leaf is covered.
B. Take a slice an uncooked potato and put in in another shallow dish. Pour a small amount of iodine on the white part of the potato.
C. After a few minutes, pick up the potato slice with tweezers and wash it with water. What color has the potato changed to?
D. After about two hours pull the leaf out of iodine with the tweezers and rice it off. What color is it?
Day 2:
A. Dump out the alcohol and place the leaf in a shallow dish. Pour enough iodine on it so that the leaf is covered.
B. Take a slice an uncooked potato and put in in another shallow dish. Pour a small amount of iodine on the white part of the potato.
C. After a few minutes, pick up the potato slice with tweezers and wash it with water. What color has the potato changed to?
Can you see the purplish-blue spots on the potato?
D. After about two hours pull the leaf out of iodine with the tweezers and rice it off. What color is it?
It is hard to tell from this photo but it has turned a bluish-purple color. Can you see the purplish water spots beside the leaf?
Clean up everything and be sure to clean the sink with plenty of water as it will rust metal.
"Iodine is used to test for the presence of starch, because when iodine is mixed with starch the mixture will turn a deep blue color. Starch is a chemical that we use as a food source. The starch contains energy and our bodies break the starch down and convert the energy contained in it into energy that our bodies use to keep us alive. Plants produce their own food, converting energy from their surroundings into energy which sustains them."- Exploring Creation with General Science by Dr. Jay Wile
