### Physics and Entertainment

We all heard about the story of Newton's pleasant experience with a falling apple. It may not be the first time that the great man saw something falling in his life; it certainly was not the first time he saw a falling apple either. An idea, however, dawned upon Sir Isaac Newton when he saw that particular apple falling off a tree in his backgarden- a Eureka moment for Newton. It changed the way people perceived the world around them for ever: the theory of gravitation was born. It was intuition that made Newton understand what gravity was all about.

In addition to Newton's Law of Gravitation, he came up three laws to describe the motion of objects. They came to be known as Newton's Laws of Motion.

Newton's Laws of Motion

1. An object is at rest or moves along a straight line unless it is acted upon by an external force.
2. The rate of change of momentum an object is directly proportional to the force that caused it.
3. Every action has an equal and opposite reaction.

If you broaden the understanding of Newton's Laws, you can do it easily. First, try it with your friends as a challenge. If you can't, then watch the video to see how it could be done.

#### Friction - necessary evil

Friction is evil, yet essential. Those of us, who have experienced unglamorous falls on hardened snow in wintry months, know very well what could happen in the absence of friction.

Here is a clip that shows how coconut pluckers in Sri Lanka defy gravity, thanks to friction - impoverished, but ingenious. They reach the height of 6-7 double-deck buses in a matter of seconds to pluck coconuts!

#### Stirling Engine

The Stirling engine was invented in 1816 by Rev. Robert Stirling of Scotland. Unlike steam engines, the Stirling is a very simple engine, that works on the principle of expansion / contraction of a trapped mass of gas. It became popular with the industrialists in the 19th century before being shadowed by the advent of electric motor.

These engines have become popular again due to the miniature models promoted by science enthusiasts.I bought one recently and it was just magical to watch - pretty fast and elegant working.

This is how it works:

You can get a quality working model from Amazon to learn and have fun with the Stirling engine. Please click the image below:

Don't use petrol as the fuel for the lamp - dangerous and inflammable; instead, you can use 90% strong rubbing alcohol.