Step 1: Cut a paper towel in half and fold it a few times so it will fit into the plastic bag.
Step 2: Soak the paper towel with water, squeeze out the excess and put it into the bag. Smooth it so that it’s relatively flat.
Step 3: Plant two or three beans or seeds about 1 1/4 inches (3 cm) from the bottom of the bag, on the same side of the paper towel. Don’t worry if they don’t stay in place, but if necessary, stuff a little piece of paper towel into the bottom of the bag so the seeds don’t sit in water.
Step 4: Seal the bag partway, but leave an opening near the top so the plants can get some air.
Step 5: Tape the bag in a window with the beans facing you so you can watch them as they grow.
Safety Tips & Hints:
Dried beans are choking hazards for small children.
This experiment will work best with beans that are not too old and haven’t been irradiated. You can soak them overnight before doing the experiment to make them sprout more quickly.
For this experiment, choose as window where the beans you plant will get plenty of light, but won’t be blasted by intense sun all day.
The Science Behind the Fun:
Seeds, such as dried beans and peas, contain dormant baby plants. Dormant literally means “sleeping”. These tiny plants need certain signals to make them “wake up” and emerge from the seed. Germination is the name for the processes the embryonic plant goes through to sprout from the seed and form leaves.
Environmental signals that plants need to germinate include adequate light, air and water. Temperature can also play a role in germination.
When a plant first sprouts, it gets the nutrients it needs from the seed. in this experiment, you can see the seed shrink as the plant grows. As a plant matures, it will depend on roots and leaves to collect the energy it needs. Once it reaches a certain size and completely uses up the nutrients in the seed, your window sprout will have to be transplanted to nutrient-rich soil to survive.