Favorable Growth Conditions
If you've received a supply of Mexican jumping beans, you could perform an experiment to see how long it takes them to hatch. The moth larvae inside the bean hatch after about six months. During that time, you could place jumping beans in different containers, such as shoe boxes, glass jars, glass jars with lids, or out in the open. Or, you could put them in different climates, such as cold, warm, direct sunlight or no sunlight at all. See what conditions are most favorable to hatch the moth larvae inside your jumping beans.
Growth Weights
After about six months, an adult moth will emerge from the jumping bean. As an experiment, you could see if the jumping bean increases at all in size or weight during the six or fewer months before it hatches. You could combine the previous experiment about growth conditions with this one, and see if any conditions promote rapid growth. After the moth has hatched, you can weigh the casing, and, by performing simple subtraction (of the casing's weight before and after the larvae hatch), see how much the moth inside weighed.