Want to try a neat trick with your kids? Have your children stand within arm’s reach of the wall. Ask them to hold out their right arms and touch the wall with their fingertips. Now, tell them to rub the inside of their arms briskly for about ten seconds. Now tell them to touch the wall again with their fingertips. Won’t they be surprised when their fingers won’t reach anymore. Their arms shrunk! Try it – it really works!