Alpha science classroom： Test for Starch in Plants

Light and action are one of the sources of the growth ability of green plants, so children know that there is also a white substance in plants as growth energy. Today, Alpha Science Classroom teaches kids to test starches in plants, an amazing biological science experiment for kids that unleashes the magical energy found in green plants. At the same time, children can also learn about the wonderful connection between nature and humans through these kid's science experiments.

Alpha science classroom: Test for Starch in Plants, what materials do you need?

• Two plants

• Beaker or glass jar

• A pot on the stove

• Ethanol

• Iodine solution

• Tweezers

Alpha science classroom: Test for Starch in Plants, experimental steps

Step 1: Children place one plant in a dark room for 24 hours; place the other plant on a sunny windowsill and wait 24 hours.

Step 2: The children fill a beaker or jar with ethanol and place the beaker or jar in a pot filled with water.

Step 3: Children carefully use the heating pot until the ethanol begins to boil. Then remove it from the heat before.

Step 4: Children use tweezers to dip each leaf in the hot water for 60 seconds. 

Step 5: Children place the leaves in a beaker or jar of ethanol for two minutes (or until they turn almost white).

Step 6: Children place them each in a shallow dish, then cover the leaves with some iodine solution and observe.

Alpha science classroom: testing starch in plants, the science behind it

Photosynthesis is the process in which green plants (primarily) convert energy from the sun’s light into usable, chemical energy. Plants require energy for growth, reproduction, and defense. Excess energy, created from photosynthesis, is stored in plant tissue as starch. Starch is a white and powdery substance. It houses glucose, which plants use for food. The presence of starch in a leaf is reliable evidence of photosynthesis. That’s because starch formation requires photosynthesis.

The alpha science classroom tells the children that hot water kills the leaves and alcohol breaks down chlorophyll, causing the leaves to lose their green color. When you put iodine on the leaves, one of them will turn blue-black and the other will turn reddish-brown. Iodine is an indicator that turns blue-black in the presence of starch. The leaf that is in the light turns blue-black, which indicates that the leaf has been photosynthesizing and producing starch.

Try this test again with a variegated leaf (a leaf that is both green and white) that has been in the sun. A leaf needs chlorophyll to photosynthesize - based on this information, where do you think you would find starch in the variegated leaf?

Plant starch is another kind of energy material in plants. This time, the alpha science classroom presents children's biological science experiments to let them learn about plant starch and the diversity of plants. Through these kid's science experiments, children can learn about nature and learn how to protect it to make our earth greener and healthier, and grow up to be the best "little environmentalist".