Physics on Pitara Kids Network

Why is it Harder to Walk Uphill?

Sat, 25 Nov 2000 01:07:23 +0000

Raju heard the familiar cry of the ice-cream seller reach his ears, clear as a bell, even from his fourth floor apartment. He flew out of the flat and bounded down the stairs four steps at a time. The lift being under temporary repair, he had to take the stairs. He arrived downstairs a little breathless, and extremely impatient to have his ice-cream.

How Does Ice float?

Thu, 16 Dec 2004 03:41:03 +0000

A cool glass of water topped with huge chunks of ice is sure to quench your thirst on a hot summer day. But, before you guzzle the water, look at how the ice floats on the water surface. How do these large ice pieces manage to stay afloat?

Ice floats because it is less dense than water. (If you take a one-litre container with ice and weigh it, it will be lighter than a similar container with water.)

Albert Einstein

Fri, 02 Nov 2001 01:20:54 +0000

German-American physicist Albert Einstein contributed more than any other scientist to the 20th-century vision of physical reality. In the wake of World War I, Einstein’s theories, especially his theory of relativity, seemed to many people to point to a pure quality of human thought, one far removed from the war and its aftermath. Seldom has a scientist received such public attention for having cultivated the fruit of pure learning.

Born in Ulm in Germany on March 14, 1879, Einstein’s parents were nonobservant Jews who moved from Ulm to Munich when Einstein was an infant. The family moved yet again to Milan in Italy in 1894, when the family business of manufacturing electrical apparatus failed.

How do Satellites Stay Up?

Thu, 24 Apr 2003 16:34:46 +0000

Satellites orbit the earth because of the force of gravity. To understand why this happens and why the satellite does not get pulled in and fall, we have to understand what forces do. A force will change the motion of an object; it might speed it up, slow it down or change its direction. For example, if you are running and someone pushes you from behind, you speed up (the force is in the direction of your motion). But if someone pushes you in the chest when you are running, you slow down (the force is in the opposite direction to your motion). If you are running and someone pushes you from the side, you move away from them, changing your direction. (the force is at right angles to the motion). This idea is called

Why do We Cup Our Hands When We Shout?

Wed, 21 Aug 2002 23:23:05 +0000

“Go on Sanjay, go on,” we shouted. It was the annual sports meet in our school and the 100 metres sprint was on. The White House runner Deepak was giving our Blue House sprinter, Sanjay, tough competition.

As the sprinters neared the finishing line, and the shouts turned into screams, I noticed something remarkable. Everyone had cupped their hands around their mouths while shouting.

Elevator Physics

Sun, 17 Apr 2005 15:59:12 +0000

You get into an elevator (or a lift, as we sometimes call it) and for a second or two, just as the elevator moves down, we feel weightless. On the other hand, if we go up in an elevator, we suddenly feel heavier just as the elevator lurches upwards.

To understand this feeling of weightlessness, we need to understand a few basic things first.

Why does a Cricket Ball Swing?

Sun, 11 Mar 2001 20:21:37 +0000

How many times have all of us heard that the former captain of the Indian cricket team, Kapil Dev, was one of the greatest out-swing bowlers of all times. Indeed! He took more than 430 wickets in Test cricket. But, do you know how a cricket ball swings?

The term ‘swing’ refers to the movement of the cricket ball in the air after it leaves the bowler’s hand, which takes the ball away from or towards the batsman. If the ball moves away from the batsman it is called an out-swinger; if the ball moves towards the batsman it is called the in-swinger.

The Making of a Prodigy

Fri, 29 Mar 2002 11:31:32 +0000

When Siva Kalyan was born, his spine or backbone was deformed resulting in a lifelong difficulty in walking. But that hasn’t stopped the nine-year-old from becoming a prodigy. This child, who loves reading comics, writing stories and enjoys sketching cartoon strips, is learning advanced mathematics and physics from one of the most reputed universities in the United States of America.

The Hindu reports that Siva’s parents were in Tamil Nadu when Siva was born. His backbone was not straight, his joints were loose and the muscles were weak. Till he was three-and-a-half years old, Siva could not even crawl. Wanting the best treatment for their son, Siva’s parents moved with him from India to Australia and later shifted to the United States of America.

Marbles Teach

Sun, 10 Jun 2001 10:42:57 +0000

A moving object transfers its force to the second object and itself comes to rest. Did you understand that? No? But you will once you play this little game with marbles.

The things you need:

Clay or plasticine
Broomstick
Marbles

Step 1: Take two broomsticks and bend them around two centimetres in the centre.

Marbles Teach [Illustrations by Shinod AP]

Step 2: Seal the ends with clay or plasticine and apply some in the centre for support. The ends should be three centimetres higher than the middle. Keep five millimetres of distance between the two broomsticks for the marble to roll in between.

Against the Law of Gravity

Mon, 12 Mar 2001 05:59:45 +0000

When an apple fell on Newton’s head, he formulated the law of gravity. According to this law, every object is attracted towards the centre of the earth with a force called the gravitational force.

But if Newton were to see this ring suspended in mid-air without any support, one wonders what he would have done.

The things you need:

A ring
Cotton thread
Matchbox
Salt

Step 1: Soak the thread in salt water for sometime. Leave it to dry. Repeat this two to three times.