Challenge and have fun This interesting toy comes with two Styrofoam balls. See how long you can make the ball float. Challenge family and friends. Great party favor and holiday gift. The floating ball game is an excellent example of "Bernoulli's Principle". As air is forced around the ball it must move faster in order to "catch up" on the other side. The result is a decrease in air pressure around the ball that in turn keeps the ball in place. The force is strong enough to resist other forces acting on the ball such as a subtle tap from your finger. The force can also overcome gravity if the flow of air is strong enough. This way you can teach you can teach your kids as well. This toy is also helpful in ADHD and Autism Occupational Therapy helping building concentration and speech. High quality wood is used which makes it durable and safe for kids, edges are polished and smooth. Also this toy is handy and can be carried to different places along with us. This toy develops skills like hand and eye co - ordination, creativity and imagination, color and shape recognition, object, sound recognition and does breathing exercise.