ten little fingers - arvind gupta (4 mb pdf)

SIMPLEST SOLAR COOKERThis solar cooker has been designed by Suresh Vaidyarajan - an architect, who has found asimple solution for a tough problem. For the last one year he has been cooking his food in thissolar cooker. This is the simplest solar cooker that I have ever seen.1. There is a tremendousshortage of wood, keroseneand fuel for cooking. But canwe not use the tremendousheat of the sun to cook food?2. Take an old car tube. Ifthe tube is punctured get itpatched. Inflate the tube andkeep it on a wooden board.3. Take an aluminium-cookingvessel with a lid. Paint it blackfrom the outside. Put all theingredients for cooking Khichdi -rice, daal, salt, water etc. in thecooking pot.4. Place the cooking vessel insidethe tube. Cover the tube with apiece of plain glass. Within threehours the Khichdi will getcooked.SOLAR PINWHEELThis simple device uses the sun’s energy to rotate a pinwheel.5. What happens ? The space in the well of the tube is like aclosed cavity. Air can neither go out nor come in. The rays ofthe sun enter the glass and get trapped. Slowly, the temperatureof the cooking vessel rises and the Khichdi gets cooked.1. Fold a square paperto make a windmill.Cut along thediagonals as shown.2. Glue the corners tothe centre. Make adent (not a hole) witha pencil at the centreof the windmill3. Bend apiece of thinwire asshown.4. Cut the bottom out ofthree old tin cans. Paint theoutside of the cans black.Join the three cans togetherwith some tape to make atall metal cylinder.5. Tape the wire onthe top of the canand balance thewindmill on its tip.6. Stand the cans on two books on asunny windowsill. Watch whathappens as the sun warms the cans.The hot air inside the can rises up,sucking cold air from below. Thiscontinuous convectional current keepsthe pinwheel rotating.