ten little fingers - arvind gupta (4 mb pdf)

1. To make an air jack you will require emptyplastic milk bags, a piece of thick string orcycle valve tube and an old pen body.AIR JACK3. Place 5 or 6 thick books on the plastic bag andslowly blow air into it with your mouth. As the bag getsinflated the books get raised. How does the air jackwork? The pressure that you exert with your mouth islimited. But the large area of the milk bag magnifies thispressure and enables you to lift the heavy books.2. Tie an old pen body or a pipe tothe mouth of the bag with a string.Soda Water Cap Gears1. Collect a fewsoda water bottlecaps. Hammer a nailin their centre tomake a small hole.Cap Top2. Place two caps on a wooden plankand mesh their teeth. Put a nail throughtheir holes so that the caps can rotatefreely. Rotate one cap and see thedirection of rotation of the other cap.3. Now fix a third cap inmesh with one cap.Observe the direction ofrotation of the three caps.1. Take a plastic capof a white film reelbottle. Make a hole inits centre with adivider.2. Tightly fit the metal partof a 5-cm long refill in thishole (refills with long brasstips are best).3. Now hold the plastic refilland spin this almost perfecttop. This toy has got all theattributes of a great top - alow centre of gravity and alarge moment of inertia.