<p>The history of mirrors dates back to ancient times when human beings first saw their reflections in a pond and considered it magic. Polished stone and metal were the first man-made mirrors. Modern mirrors are made from glass with a coating of silver on the back.<br /><br /> The invention of the silvered-glass is credited to German chemist Justus von Liebig in 1835.<br /><br /> His process involved the deposition of a thin layer of metallic silver onto glass through the chemical reduction of silver nitrate. This mass manufacturing silvering process led to greater availability of affordable mirrors. Nowadays, mirrors are often produced by the vacuum deposition of aluminium (or sometimes silver) directly onto the glass substrate.<br /><br />A plane mirror which is flat reflects light without changing the image. A convex mirror has an outward bulge and makes an object looks bigger. A concave mirror has a very shallow bowl shape and makes the object looks smaller.<br /><br />The concave parabolic mirror is the principal element of a reflecting telescope. Mouth mirrors or “dental mirrors” are used by dentists to allow indirect vision and lighting within the mouth. Rear-view mirrors are widely used in and on vehicles (automobiles and bicycles) to allow drivers to see other vehicles coming up behind them.<br /><br />Here are some fun experiments which you can do using simple mirrors.</p>.<p>Exploring symmetries<br /><br />You can explore the beautiful world of symmetry with mirrors. Many leaves like the Peepal (Ficus religosa) or the Kachan (Bahunia) have two almost similar shapes on both sides of the midrib. On placing a plane mirror on the midrib you will be able to see the whole leaf. </p>.<p>Mirror script<br /><br />Try writing your name in mirror script – which means you should be able to read it in the mirror. Try writing ‘Toys are fun’ in mirror script. It will take you a while before you get a feel of it. But it is going to be great fun.<br /><br /> Which letters of the alphabet do not change in the mirror? Can you write whole words which do not change in the mirror? After a few words you can also try writing a short sentence which does not change in the mirror.<br /><br />If you were to hold a mirror along the dotted lines you will see the whole alphabet. The letters ‘A’ and ‘B’ have only one line of symmetry. But ‘H’ has two and ‘O’ has infinite lines of symmetry. </p>.<p>Snaky line<br /><br />Draw a snaky line on the ground. You can also use a rope or a garden hose. Now hold a mirror on top and walk with the line between your legs. You should not step on the line nor look at it directly. You can, of course, look at the line through the mirror.</p>.<p>Mirror puzzle<br /><br />There is a simple pattern designated the ‘Master Picture’. You have to place a plane mirror on this ‘Master Picture’ and make all the patterns shown below. It will not always be easy and some of them might be quite impossible to make! </p>.<p>Make a periscope<br /><br />A periscope is an instrument for observation from a concealed position. In its simplest form it consists of a tube with mirrors at each end set parallel to each other at a 45-degree angle. Tanks use periscopes extensively: they enable drivers or tank commanders to inspect their situation without leaving the safety of the tank. Periscopes allow a submarine, when submerged at a shallow depth, to search visually for nearby targets and threats on the surface of the water and in the air. When not in use, a submarine’s periscope retracts into the hull. <br /><br />You can make a simple periscope using a cardboard pencil box, two plane mirrors and some tape. Partly cut two ends of the box and fold them at right angles. Place two mirrors and shown and tape them. With your periscope you can sit below a table and still see the stuff which lies on the table. Watch this video http://www.youtube.com/watch?v=Nzwc5zBl5vM</p>
<p>The history of mirrors dates back to ancient times when human beings first saw their reflections in a pond and considered it magic. Polished stone and metal were the first man-made mirrors. Modern mirrors are made from glass with a coating of silver on the back.<br /><br /> The invention of the silvered-glass is credited to German chemist Justus von Liebig in 1835.<br /><br /> His process involved the deposition of a thin layer of metallic silver onto glass through the chemical reduction of silver nitrate. This mass manufacturing silvering process led to greater availability of affordable mirrors. Nowadays, mirrors are often produced by the vacuum deposition of aluminium (or sometimes silver) directly onto the glass substrate.<br /><br />A plane mirror which is flat reflects light without changing the image. A convex mirror has an outward bulge and makes an object looks bigger. A concave mirror has a very shallow bowl shape and makes the object looks smaller.<br /><br />The concave parabolic mirror is the principal element of a reflecting telescope. Mouth mirrors or “dental mirrors” are used by dentists to allow indirect vision and lighting within the mouth. Rear-view mirrors are widely used in and on vehicles (automobiles and bicycles) to allow drivers to see other vehicles coming up behind them.<br /><br />Here are some fun experiments which you can do using simple mirrors.</p>.<p>Exploring symmetries<br /><br />You can explore the beautiful world of symmetry with mirrors. Many leaves like the Peepal (Ficus religosa) or the Kachan (Bahunia) have two almost similar shapes on both sides of the midrib. On placing a plane mirror on the midrib you will be able to see the whole leaf. </p>.<p>Mirror script<br /><br />Try writing your name in mirror script – which means you should be able to read it in the mirror. Try writing ‘Toys are fun’ in mirror script. It will take you a while before you get a feel of it. But it is going to be great fun.<br /><br /> Which letters of the alphabet do not change in the mirror? Can you write whole words which do not change in the mirror? After a few words you can also try writing a short sentence which does not change in the mirror.<br /><br />If you were to hold a mirror along the dotted lines you will see the whole alphabet. The letters ‘A’ and ‘B’ have only one line of symmetry. But ‘H’ has two and ‘O’ has infinite lines of symmetry. </p>.<p>Snaky line<br /><br />Draw a snaky line on the ground. You can also use a rope or a garden hose. Now hold a mirror on top and walk with the line between your legs. You should not step on the line nor look at it directly. You can, of course, look at the line through the mirror.</p>.<p>Mirror puzzle<br /><br />There is a simple pattern designated the ‘Master Picture’. You have to place a plane mirror on this ‘Master Picture’ and make all the patterns shown below. It will not always be easy and some of them might be quite impossible to make! </p>.<p>Make a periscope<br /><br />A periscope is an instrument for observation from a concealed position. In its simplest form it consists of a tube with mirrors at each end set parallel to each other at a 45-degree angle. Tanks use periscopes extensively: they enable drivers or tank commanders to inspect their situation without leaving the safety of the tank. Periscopes allow a submarine, when submerged at a shallow depth, to search visually for nearby targets and threats on the surface of the water and in the air. When not in use, a submarine’s periscope retracts into the hull. <br /><br />You can make a simple periscope using a cardboard pencil box, two plane mirrors and some tape. Partly cut two ends of the box and fold them at right angles. Place two mirrors and shown and tape them. With your periscope you can sit below a table and still see the stuff which lies on the table. Watch this video http://www.youtube.com/watch?v=Nzwc5zBl5vM</p>
