Science Projects And Inventions

YOU NEED: • A ring and some string       When an ice skater spins with outstretched arms, then quickly lowers her arms, her speed of rotation increases enormously. This is because her arms are suddenly forced to move in a smaller circular path. This effect can be demonstrated with a finger ring and a piece of string. Attach the string to the ring so that it hangs down, as in the illustration, while you hold the ends of the string. Now twirl the ring in a circle about six inches (15 cm) in diameter. As you twirl the ring, pull on the ends of the string. The ring speeds up.   HOW DOES IT WORK?   When the ends of the strings are pulled, the ring is forced to go around in a smaller circle, causing its angular velocity to increase suddenly. Much the same thing happens when water goes down more...

YOU NEED :

• A piece of thick plastic
• A tub
• Some water
• Some liquid detergent

  Cut out of plastic in the shape of a boat bottom, having one side pointed and the other straight. In the centre of the straight side cut a small ‘V’ shaped notch. Place this shape in a tub of water. The shape will not move once the water is still. Without shaking the water, carefully  put a drop of detergent in the 'V’ shaped notch that you had cut earlier. You will see that the piece of plastic begins to move.   HOW DOES IT WORK? This  happens because the detergent disturbs the surface tension of the water and the plastic moves Forward.

YOU NEED : 

• Cardboard tube 
• An apple              
• A rubber bail       
• An Iron nut         

Do you know that the time taken for a pendulum to swing is not related to the weight attached to it but to the length of string it is attached to. You can test this by taking a number of strings of the same lengths and attaching to it different weights, then again by taking different lengths and attaching the same weight to it, and so on.   HOW DOES IT WORK? Since the pull of gravity is the same on all the objects, irrespective of their weight, all the objects swing at the same speed. This is why the weight of the object has no relation to the swing of the pendulum.

YOU NEED –

• Two cardboard disks about 3’’ (7.5 cm)
• An empty wooden spool
• Some string

  Cut out the disks from a cardboard. Use glue to stick them to the ends of an empty wooden spool. Take the string and wrap some around the spool. Now pull the free end as in the illustration. The question is will the spool roll away? Come towards you or will it stay where it is? The answer is the spool will roll towards the person pulling it.   HOW DOES IT WORK? A tug on the string it would seem will make the spool roll away from you. But that is impossible because you are actually pulling it towards you. No resistance is offered by the larger discs as a result of which the spool rolls towards you, while the string keeps winding around the spool. more...

YOU NEED:

• A table
• Three sheets of newspaper
• A pencil

1.            On the side of a table spread the three sheets of newspaper. Place a new pencil halfway under the paper. Allow the other half of the pencil to project over the edge of the table as shown in the illustration. Either strike the end of the pencil with a quick blow of your hand, or hit it with a hammer. You will be surprised to see that the newspaper will not tear, but the pencil will break in half. Similarly, one can break a ruler or a thin wooden board. 2.            Fold new ten rupee note lengthwise. The crease should be sharp. You can tell your friends that it will act like the edge of a knife, and chop a pencil in half. Tell someone to hold the pencil horizontally by grasping the two ends- Hit the more...

YOU NEED: • A hairpin • A table knife                     You can actually make a hair pin move along the edge of a table knife. Place a hairpin over the edge of a table knife and hold the knife horizontally, with the hairpin leaning toward you as shown in the illustration. Your arm must not rest on the table. Now even if you want to keep the knife steady  it is not possible. The hairpin will be "moving" towards your hand. If you make the hairpin lean the other way it will move forward and fall off the edge of the knife. Instead of a hairpin, a straightened out paper clip bent it in the middle, will also serve the purpose.   HOW DOES IT WORK? You  cannot prevent your hand from jiggling. Each jiggle lilts the pin a trifle. Because the hairpin is in a more...

YOU NEED: • A Cork                      • A Knitting Needle • Four, thin pieces of plastic                           ; • Proximity to a tap   Bore a hole through the centre of a cork and insert a knitting needle through it. Make six slits on the surface of the cork and wedge thin slices of plastic into each slit. Hold the turbine under a steam of water. The turbine rotates as the water hits the vanes. The speed will depend upon how fast the water flows. This is how water falls from the top of the dams on large water turbines which rotate and generate electricity.   HOW DOES IT WORK?   The knitting needle passing through the cork serves as a central shaft that allows the cork to rotate. As the water falls on the thin strip of plastic, it pushes it down. This makes the cork more...

YOU NEED: • A clear plastic jar • A marble   Take a transparent plastic container and put a marble inside it. Now move the container in a circular motion, duly maintaining contact with the table top. The marble moves up the sides of the container and revolves around the walls.   HOW DOES IT WORK?   This is caused by the centrifugal force which moves outwards and upwards those objects that are travelling at high speeds. While travelling in your car you feel a similar pull, outwards, while taking a turn around a corner at speed. This is how stuntmen ride the motorcycle inside a round cage in the circus.

YOU NEED : • An empty plastic bottle • A sharp pencil Gravity disappears inside a freely falling container. This is one trick that should preferably be performed outdoors. Make two holes on opposite sides of a plastic bottle near the bottom with a sharp pencil. Fill the bottle with water having put your thumb and forefinger over the holes. Should you remove your thumb and forefinger, gravity will force the water to come out. Interestingly, if you hold the bottle at a height and let it fall, the water will remain in the bottle. It is much like a spacecraft as it orbits Earth.   HOW DOES IT WORK? In a gravitational field, everything falls at the same speed no matter what its weight is or what it is made of. In this particular experiment, the water does not come out because both the water more...

YOU NEED: • A coin • A paper match • A transparent plastic cup • A pocket comb   Gingerly balance a coin on Its edge. Place a paper match stick on top as in the Illustration. Now upturn an empty glass over the coin and the match stick. The problem: Try to knock the match off without disturbing the coin. There is a condition: You are disallowed from touching the glass and you cannot shake the table because the coin will fall.   HOW DOES IT WORK? The trick is done by static electricity. Take a pocket comb and rub it vigorously on your shirt or skirt. Now hold the comb close to the glass and the match will drop. The coin remains undisturbed.