LEND ME YOUR EAR, I WILL TELLYOUR AGE

If a bell is stroked in a place of worship, it vibrates; set the air molecules in vibration; molecules strike eardrum and vibrates it; our brain interprets the vibrations and we perceive the sound. We understand that the vibrations are the basis for the sound. Number of vibrations taking place in one second is called "frequency". Suppose there are 100 vibrations per second, we say, the frequency is 100 hertz or 100 Hz.

    The human ears are extremely sensitive to the frequency range 2000 hz -5000 hz.  All humans at any age can hear up to 8000 hz clearly.  Persons of age over 50, cannot hear 12000 hz.
Over 40 - can hear up to 15000hz
over 30- up to 16000hz
above 17 khz, even young persons under 25 age, struggle to hear that frequency.  Only newborn may hear them.
    Why does our hearing appear to 'age'.  Our ears have distinctive, spiral-shaped part called the cochlea and it is filled with fluids and tiny hairs called cilia.  These cilia are vibrated by air molecules (sound waves) and we sense the sound.  The most sensitive cilia get destroyed as we age.
    The cilia do not regrow.  Loud music from headphones is harmful. So, do not raise the volume beyond allowed level.
     Many animals can hear higher frequencies.

Dog- 64hz -44khz
Mouse- 900hz-79khz
cat-55hz -77khz
dolphin -150hz –150khz

    We, humans can hear up to 8 k hz comfortably, but dolphin can hear up to 150khz.
    The sound waves which have frequencies more than 20 khz (that we cannot hear) is called ultrasonic waves.  Many medical instruments use ultrasonic waves for scanning purpose.

NOTE: 1. When you go near an electrical transformer, you hear a humming sound. The frequency of electric current is 50 hz and that is also the frequency of humming noise.
Note 2. All objects like wine glass, bell, table, plate, wall etc. have their own natural frequency.
Note 3. As we age, our vision, hearing, taste, muscle strength may get eroded. Our teeth, hair may fall, but our determination, thoughts, mind, enthusiasm should remain young and strong as ever.

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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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