Episode 10

S3 E10: PAPER MOVIE MACHINES: Bibi watches Mr. Wizard swing a light in a circle to produce a streak of light. He explains that the so called persistence of vision is the reason motion pictures create the illusion of movement. DOLPHIN LANGUAGE: Dolphins are trained the same way you probably trained your pet. When it obeyed your command, you gave it praise or a bit of food. Once a dolphin associates a reward with doing something, the trainer precedes it with a command — a hand signal, for instance. Soon the dolphin recognizes the hand signal and responds with the desired behavior. HEAT EXPANSION: Darren knows that metals expand when heated and contract when cooled. Mr. Wizard shows him a block of wood with thumb tacks and a metal rod resting on a needle over another block of wood. A soda straw acts as a pointer to magnify the movement of the rod. ROPE ON WRIST - Jacki and Chris have ropes tying their hands together. The ropes loop so that the two children are tied together. Mr. Wizard challenges them to separate themselves. Chris tries and fails. PETRIFIED FOREST: The high plateau country of northeastern Arizona is mostly a semi‑arid land of hills, canyons, and plains. The plants and animals that live here are typical of desert‑dwelling species. But if you go to the right place, you'll come to a most unusual forest. Fallen logs, to be sure, but no longer made of wood. They've turned to stone or petrified. PAPER TEAR: Mr. Wizard hands Phil a piece of paper with two tears in it and challenges him to pull the paper apart ending up with three pieces. Phil pull the two end pieces and finds that he ends up with two pieces instead of three because he cannot put equal force on both tears. KILLDEER ACT: The nest on the ground is camouflaged but the eggs could be a quick meal for this black snake that feeds on birds eggs. Before the snake has found the nest, the mother killdeer flaps her wings to attract the snake’s attention. She flops around on the ground as if injured. The snake thinks it’s found an easy prey. Once it has been lured away, the killdeer returns to the nest. "MOBILE CHALLENGE: Lauri examines a mobile made of pieces of wood of equal weight with holes drilled in them at equal distances. Mr. Wizard explains that she has to multiply the distance, represented by the holes, by the weight, represented by the number of sticks. Some of the sticks are covered by pieces of paper. By calculating the weight multiplied by the distance on one side of an arm of the mobile she calculates the value of the weight hidden under a piece of paper on the other side.