Seriously BIG FUN! These dinos are 5 1/2 inches long before you soak them in water-14 inches when they reach full size. Can be dried out and then grown again. We tried them and were amazed how big they grew. Put your grow dino in a tub or bucket of cool water and watch it grow! It will keep kids interested in how much they change day to day. Build them a home, they will never dissolve or turn to mush. What a fun way to teach measurement! Dinosaurs vary (Triceratops, Brontosaurus, Velociraptor or Stegosaurus). Your dinosaur will be chosen at random but if you buy more than one, we will send different ones, unless you ask for the same. Growing animals and other things (brains etc.!) that are made to increase in size in water are made up of two polymers. One is poly(vinyl acetate) which keeps the original proportions and shape of the item or creature and the other polymer is polyacrylamide which is the super absorbent polymer. The growing creatures have many teaching applications in science and math, including graphing, drawing conclusions, and measurement using linear, mass and volume.