Sparrow-in or out ?
Sparrow In or Out
Articles Required: A white cardboard piece, thin white string and a sketch pen.
Take the cardboard piece and the with the help of sketch-pen draw the pretty figure of a sparrow on one side, and of a cage on the reverse. The cage should be big enough to accommodate the bird. Now just make two holes at equal distances on the two sides of the
cardboard piece. Slip the string through them and be off with worries as your game is ready.Do you know on what principle this works? You'll be surprised to learn that the motion pictures run on the same principle. The principle is that whatever we see leaves its impact on our eyes for around 1/16th of a second. The scientists took advantage of this fact and gifted the mankind with this exciting invention.
And here too because of this property of the eye, you would see the sparrow caught in a cage. Now as you twirl the string rapidly, the cardboard piece rotates and the images of sparrow and cage quickly succeed each other-creating an impression that there is only one picture, and that of the sparrow inside the cage.
Cold water-heavy, Hot -light:
Cold Water -Hot water
Articles Required: Two empty bottles hot and cold water, a thin sheet of card board, blue or red ink.
Put blue or red ink in a bottle and fill it with hot water upto the brim. Take, the second bottle and pour cold water in it. Now keep a cardboard piece on its mouth,press it with pour fingers and invert the bottle on top of the other one. Once the mouths of the two bottles come in alignment gently pull out the cardboard piece. The water in the two bottles will come into contact with each other and soon you'll notice that the coloured water from the bottom starts rising upwards, and the clean water starts flowing down. Do you know why it happens like this? This just goes to prove that the hot water is lighter in comparison to cold water. And that is because its specific gravity is less than that of the cold water.
Hot air light-Cold air Heavy:
Hot air-Cold air
Articles Required: A stick one candle, two identical paper bags, little thread, cello tape.
You know that when heated the air becomes lighter. But if you're asked to prove this fact, would you be able to do it? No? Come, let's show you a simple way out of it. First of all, with the help of cello tape and threads hang the paper bags at both the ends of a stick as
shown in the picture. While doing it, make sure that their open faces point downwards. Hang this stick from the centre, so that it takes a
horizontal position i.e. parallel to the ground. Once the stick becomes stationary, take a candle under any of the two envelopes ensuring that none of the envelop catches fire. After some time, you'll notice that the end under which you're holding the candle starts rising up. Do you know why? As the air in this envelope gets hot it becomes lighter. And. since the other side is heavier because of cool air, it sinks down. How simple it is.