Test the effects that microwaves have on the growth of seeds. Use bean seeds for this experiment. Beans are easy to grow indoors any time of year. You’ll need a packet of bean seeds, seven small pots, a ruler, labels and a bag of potting soil.
Divide the beans evenly into seven groups. Label each of your pots with the labels “Control,” “30 seconds,” “1 minute,” “1.5 minutes,” “2 minutes,” 2.5 minutes” and “3 minutes.”
Plant the first group of seeds in the “Control” pot. Microwave the next group of seeds for 30 seconds. Then plant them in the corresponding pot. Continue with each group of seeds, microwaving them for 30 additional seconds and planting them in the corresponding pot.
Place the pots in a sunny place. Water them regularly and give each pot the same amount of water. Keep notes on the progress of each group. Note the day you first see a sprout break through the dirt. Use a ruler to measure and record the growth of each group of sprouts. Track the growth for at least two weeks.
Test the effects of water boiled in a microwave on plant growth. Begin with two identical plants. It is best if you use cuttings transplanted from the same parent plant so that the plants share the same genes, but you can also use small plants of the same species and that are about the same size at the start of the experiment.
For two to four weeks, water one plant with water boiled in a microwave and water the other with water boiled in a pan on the stove. In the microwave, use a glass container to boil the water because plastic containers can leech chemicals into the water. It’s easiest to boil a large quantity of water and store it in the fridge or on the counter. Make sure you clearly label which container has microwave-boiled water and which has pan-boiled water. Label your plants clearly, too, so you know which gets which water. Give each plant the same amount of water at the same intervals and make sure they each get the same amount of light.
To record the progress of the plants, take digital photos of them every two to three days. Compare their progress at the end of the experiment.
A household microwave oven can lend itself to many other good science fair projects and experiments. Consider designing your own experiment to test how microwaves affect different things.