This shark that starts off 6.5 inches (14 cm) will grow to over 16 inches in about 10 days. Teaches about water absorbing polymers, increases in mass, measuring and charting, and simply impressive science. Place the Ginormous Grow Shark in a tub or bucket of water and watch it grow over 1.50 feet long and 9" wide in 7 to 14 days! Imagine a 1.50 foot shark right in your own house! Take it out of the water and watch it shrink back to its original size, over time as it dries.