### DISCOVER IT – 1

This year is being celebrated as an important anniversary year for science . One century ago, in the year 1905, young Einstein published four pathbreaking papers in physics. Each of these papers was of historic importance. In honour of this great year in the history of Physics, we are celebrating its centennial as “The International Year of Physics”.

Here at Indrandhanush we will be observing this year in a special way, with a journey of discovery.

Would you too like to become a great scientist, like Einstein, or Archimedes, like Aryabhata, Marie Curie or C.V.Raman ? How does one become a great scientist ?

You don’t become a great scientist by mugging up books on General Knowledge for taking part in quiz competitions. You don’t become a good scientist by learning lessons by heart and getting good marks in examinations. You don’t become a scientist until you learn to understand things thoroughly. And understanding things deeply is only the first step. What is most important is learning to ask questions that nobody has asked earlier and keeping at it till you find a satisfactory answer

Asking new questions and finding out the answers for yourself is the only way to do good science. So in this series of articles, we are going to suggest some important experiments that you can do yourself. These experiments can be done with simple apparatus that you can make yourself. But the questions that these experiments give rise to may not be so simple . By answering these questions, you will train yourself to become a good scientist. Let us start our journey.

The Magic Mirrors experiment:

You can do this experiment with a single pocket mirror, or with a few different pocket mirrors. You can buy these for about 5-10 rupees each from a bazaar shop.

Lets assume that you have three small rectangular pocket mirrors for this experiment. (You can do this experiment with a single pocket mirror also if you dont have three mirrors). Now make three card rectangles which cover the mirrored glass exactly. In one card rectangle cut a hole which is circular in shape. The diameter of the circle should be around 3 cm. In the second card cut a hole in the shape of a square of side 3 cm. In the third card, the hole should be in the shape of an equilateral triangle of side three cm.
Paste these three masks on the three mirrors with some sticky adhesive, and after the gum has dried, carefully clean the exposed mirrors. So now we have three mirrors in the shape of a circle, square and triangle.

Now you are ready to do this intriguing experiment. Go out in the sunlight and using the circular mirrror cast a reflection of the sun onto the shirt of a friend who is standing one meter away from you. What is the shape of the light figure which forms on his shirt ?

Repeat the experiment with the square mirror and the triangle mirror. What is the shape of the light reflection on your friend’s shirt ?

Now throw the reflection of the circular mirror on a distant white wall.(which is about 20 metres away) What is the shape of the reflection ?

Repeat the experiment with the square and the triangle mirror, throwing their reflection on the distant wall. What do you observe ? Are you surprised ? What is the reason for this puzzling experiment? Can you think of a good explanation ?

Next month, we give the explanation, and also continue our journey of discovery.