ten little fingers - arvind gupta (4 mb pdf)

FUN WITH LIGHT1. Put a mirror in a bowl so that it isat an angle of 30 degrees to thelevel of the water. When it is darkin the room, shine a torch on themirror A small spectrum of colourswill appear on the ceiling.2. Use a magnifying glassto focus rays of sunlightonto a black thread holdinga nail in the bottle. Thethread burns and the naildrops. But it won’t workwith a white thread3. Let the sun rays focusonto a dark ink spot on thepaper. The black colour ofthe ink spot absorbs the raysof the sun. The paper soonbegins to smoke and mayeven catch fire.4. Place a pencil in a glasshalf filled with water. In acertain position the pencillooks as though it hasbeen broken in two.5. Look through a thinglass of water at your ruler.The glass acts as amagnifying glass andmakes an enlarged image.6. Put a coin in an opaque teacup.Move away from the cup, and down,until the edge of the cup blocks thecoin from sight. Now slowly pourwater into the cup without movingyour head. The coin gradually comesback into view!In dimlightInbrightlight7. Cover one eye and look into a brightlight. After the eye has adjusted to the lightopen the other eye. Quickly compare thesizes of the pupils in each eye. In dim lightthe pupil is enlarged to let in more light.8. Take a shiningtablespoon. Hold theconvex (outwardbulging) part of thespoon towards you.You will see an erectand shiny image ofyourself.9. Now turn thespoon around so thatthe concave (inwardcurving) side facesyou. This time yousee a small upsidedownimage ofyourself.