THE INVISIBLE FIELDS

We have a football field, a field of valleys and hills. What exactly a field is ? It can be thought as a area containing many, many points. Each point may have a value like its height, its temperature, its greenness etc.

Consider an LED lamp. There is field of light around it. But, this is 3-dimensional field unlike surface area. The light is very bright close to the bulb and the light fads away with the distance. This kind of fields always follow 'inverse square law'. It says that the decrease in intensity (of light) is proportional to the square of the distance. Our eyes can sense the light. If you put any light sensitive-device in this field, it will be activated, example - light powered calculator.

Now consider a magnet, there is a magnetic field around it similar to the light field. But it is not visible. Only another magnet can sense it. If you put iron pins in the field, it will be attracted. A compass will be disturbed by the field.

Next, consider a mobile phone tower. It radiates radio waves or there is a electromagnetic field around it. All the mobile phone in the field are kept alive. When we move away from the field, we get "out of reach" message.

'Remote' devices, Bluetooth devices, WiFi network, - all generate electromagnetic fields around them. They connect other devices to them and keep them active.

Around any mass, plants, sun and stars, there is a gravitational field. The sun holds all the nine planets because of its gravity. The earth keeps the moon in its hold because of its gravitational field.

Electric charges have electric field around them. Moving and oscillating charges produce electromagnetic waves or field. To day, we go ' wireless way' because of these fields.

Action at a distance, without contacting is possible only because of these fields.

Tomorrow, a virtual fence made using a field, may stop us from trespassing, encroaching and invading.
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THE EARTH, A SUPER ORGANISM

JOIN MY COURSE: "Become a programmer in a day with python" A man called 'love lock' (what a name) proposed a theory called Gaia theory, named after Greek Goddess. It says, "Earth is a self-regulating organism like a human being. The organic life in it interacts with in-organic matter and maintains atmosphere, temperature and environment". Hence the earth is still suitable for the life to thrive. Imagine, in a particular place, there are lot of flowers. Some flowers are white and some are darkly coloured. We know, white reflects light and heat while dark absorbs the same. White flowers can thrive in hot climate. But dark flowers requires cold climate. The absorption and reflection balances and the environment reaches average, warm temperature at which both the flowers can co-exist. This is the essence of "Gaia" theory. On our earth, ...

THE PARABOLA

A jet of water shooting from a hose pipe will follow a parabolic path. What is the so special about parabola. Y= x^2 Draw a graph for the above equation. It will result in a parabola. This parabola is also called unit parabola. Any equation involving square will yield a parabola. Example: Y = 2x^2 +3x+3 (also called quadratic equation) X= 2 and -2, both satisfies the equation 4 = X^2. Parabolic equations always have two solutions. Any motion taking place freely under gravity follows parabolic path. Examples: An object dropped from a moving train, A bomb dropped from flying plane, A ball kicked upwards. If a beam of light rays fall on the parabolic shaped mirror, they will be reflected and brought to focus on a point. This fact is made use of in Dish Antenna, Telescope mirrors, etc. ...

DISORDER IS THE "ORDER OF THE DAY"

Imagine a balloon full of air. The air molecules are moving randomly inside the balloon. Let us pierce the balloon with a pin. The air rushes out. Why should not the air molecules stay inside the balloon safely and ignore the little hole? That is not the way the world works. The molecules always "want to occupy as many states as possible". Hence the air goes out in the open to occupy more volume. The things always goes into disorder (entropy) and the disorder increases with time. The above statement is what we call "second law of thermodynamics". Consider a cup of coffee on the table. Suppose the heat from entire room flows to your cup of coffee, the coffee will boil and the rest of the room will freeze. Freezing means bringing things to order and arrangement. It violates the second law. Hence it will never happen. Hence heat must flow from high ...

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