Which bouncy ball jumps the highest? Who has the best bouncy ball? In just ten minutes, children can find out about this cosmos experiment set. With the special granulate and the different moulds, children can mix spherical and square bouncing balls in a variety of colours themselves. Especially cool is the noctilucent rubber, which glows brightly in the dark. If he then gets a pair of wiggly eyes, it's really fun. If the first balls are dry after a few days and have lost their bounce, you have to make new ones. How good that the granules in this set are enough for up to 20 power balls. Exciting info texts and fun facts explain why some colours glow in the dark and how, for example, the animals of the deep sea make use of them.