Draw 1 inch measurements along one side of a foam poster board and number the marks. Attach a gummy worm, a rubber band cut to the same length as the gummy worm and a craft elastic cord also cut to the same length as the gummy worm, to the top of the poster board with thumb tacks. Pinch the gummy worm against the poster board directly below the thumb tack to keep the worm from ripping off. Begin to slowly pull the gummy worm down the poster board until it breaks. Record the inch mark the worm reached before breaking. Repeat with the rubber band and elastic cord, recording the length before each item broke. Write down your findings.
Lay a standard ruler onto a flat surface, such as a table, and tape the two ends down with duct tape to keep the ruler from moving. In a notebook, record your hypothesis on how far you think the gummy worm will stretch and why you think the worm will stretch to that length. Lay a gummy worm directly below the ruler, leveling up one end with the 1 inch mark on the ruler. Pinch that end down enough that the worm won't move, then gently begin to pull the worm along the length of the ruler until the worm breaks. Record the length mark on which the gummy worm broke.
Test the stretch capability of gummy worms under different conditions by freezing one gummy worm for four hours and placing another worm in direct sunlight or artificial light source for four hours. Test a third gummy worm fresh from the bag and a fourth that has been left out to stale for one week's time. Tape a standard ruler to a flat surface with duct tape at both ends once all four gummy worms are ready to be tested. Lay each worm directly below the ruler one at a time, and gently pinch the end down that lays level with the 1 inch mark. Stretch each worm gently along the length of the ruler until it breaks; record the breaking length for each worm.
Freeze a gummy worm and a length of rubber band for four hours before testing. Set another gummy worm and length of rubber band in direct sunlight or artificial light for four hours as well. Tape a standard ruler, or write one in marker, along the one side of a foam poster board. Remove a fresh gummy worm from the bag, and cut a length off a third rubber band. Make sure you have cut all rubber bands to the same length as the corresponding gummy worm. Tack each set of worms and rubber bands to the foam board with thumb tacks, only testing each group one at a time. Pull each worm and rubber band carefully down the ruler length, recording the length each breaks off. Record your findings.