Helicopter tail rotor

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We know that helicopter should have a tail rotor to counteract the torque created due to the main rotor blades rotation.

There is a special thing about tail rotor too. For example see the picture, there are two sets of blades (2x2=4). One set has two blades in a line.

why two sets? why can't they put just a 4 blade rotor just like a fan in our room?

The tail rotor rotates with a very high speed. Obviously causes noise. To reduce this they will put two sets of blades which will cut off the noise created by the other set

Why do we YAWN ?

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we do yawn. But why do we yawn?

A theory says that when we sleep our body metabolic rates go down. so we need less oxygen. But when we feel sleepy or tired, this happens we take in less oxygen but our body metabolic rates are still high so our body automatically tries to take in more oxygen. This is through Yawn. This is an involuntary action.

Heavy metals

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How actually these are formed...?

It is assumed that universe has only Hydrogen initially. Because of high pressure and heat, these hydrogen atoms combine to form higher atomic elements. The temperature and pressure at the core of SUN is capable of producing Helium from Hydrogen atoms.

But on Earth we have very high atomic number elements like Titanium, Uranium etc. How come??

These are generated because of the intense pressure and temperature caused by BIG BANG.

Volcanoes

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After the big bang, few big pieces of explosions attracted the others nearby. As they came near and near, their velocities became high and it was like a collision of huge bodies. Guess how many must have collided. This energy produced from the collision was stored in the resulting planet which is EARTH, which melted the core and hence it remains as LAVA.

Pencil fact

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Ever thought why are we able to write with pencil but not a black plastic or some other material...?

Pencil is made of Graphite which is made of carbon atoms held in the form of layer structure as shown in the picture.


These layers can easily slip, slide over. So when we write we just force them to slip and stick to the paper.
:)

Walking the first step

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so what helps us in walking. One thing is certain to feel the gravity. You may not expect this but our ears are the main organs which helps us feel gravity so that we can walk (legs are a means to walk). The ears contain minute hair inside, which act as gravity sensors.


image courtesy - http://gethealthlife.blogspot.com/2009_09_01_archive.html

Water

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We can see through water when the depth is less. When the depth becomes huge, we cannot see through it. Because water absorbs light. Guess what it looks like in oceans ..???

Vibration Damper

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What is it? why is it needed ?

We have seen a lot of sky scrapers... but how are they able to sustain any vibrations due to blowing winds, or small small earth quakes.....???

There is something which is known as Vibration Damper, which essentially means a system which dampens (lowers) the vibrations or their effect. I am here to explain you about a system i came to know...

So the picture here depicts a system in which a heavy mass is held on a rod. The whole setup is in oil. So when the building has vibration effect, the heavy mass oscillates with more amplitude on the rod. The oil obstructs the motion and hence the total energy is dissipated (in increasing the temperature of oil).

simple science - Great application isn't it??

more different dampers can be seen in the following website.

http://www.jssi.or.jp/English/eng-sib/e-sib-source.htm

Science behind the design of Tire

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From my childhood i thought that the Tire design is to have a good grip of vehicle to hold on the land. But how it happens i never knew till now...

So whats behind it?

Basically when a rotating body (surface) for example a tire, is kept on a fluid, due to the velocity at the tire surface, the fluid also gets dragged. In the process, there is lift produced which will make the tire float. For this not to happen, we need to remove the water from below the tire surface...which is done by the grooves, design of Tire.

The others things of the design shown here are basically for better strength, reliability etc.

Pistol Shrimp

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Know what?
A revolutionary concept in science and technology is going to come which is based on the behavior of a pretty small creature of sea.... Pistol Shrimp



Who could have imagined a small creature like that would develop a temperature of 10,000 Degrees Celsius????

The phenomenon- This creates a empty bubble, which on collapsing will create a huge temperature of 10,000 Deg. Celsius. Sadly, because of this, a shock wave is generated which kills the creature itself.

http://www.youtube.com/watch?v=XC6I8iPiHT8

Heat transfer in an Elephant

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We all know the best air conditioner in the world is skin. But how much comfort does it give for some huge creatures like elephant??

Here nature's astounding science can be seen. The elephant ears are so big and the blood vessels can be seen with the naked eye. As the ears flip flap the heat in the body which is brought through blood into blood vessels, is convected to the atmosphere.Thus keeping the body at comfort temperature. The load on the skin is reduced a bit isn't it??

Funda used in hospital

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We all see that oxygen/ artificial breathing is done to a patient, the gas/air is sent through water so that it carries some moisture with it.
- This is done to ensure that the mucous layer in the wind pipe doesn't dry up.
:)


People use oxygen mask but why does it have holes....when tubes are used to send the oxygen clearly the tube doesn't close the total hole.... ever wondered why???
- Pure oxygen is dangerous. Patients are given in air with enriched oxygen.

The wonderful nature

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Whats special about Penguin??

In Penguin, since it lives in very cold places, there has to be a way of saving the heat in the body... otherwise the obvious thing is - it'll be dead. The blood vessels of penguin, veins will be inside arteries. This way they could decrease the heat loss to atmosphere.
:)

The fog in the metro-cities

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Why the fog in the metro-cities is extremely high???

The phenomenon is here...
Metro-cities air is highly polluted because of smoke particles, carbon dioxide,carbo monoxide etc etc..

when the temperature falls down at night, the water vapor in the air condenses on the particles and thus a huge fog is created.

Metal Rubber

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We all know the polymer rubber... but ever heard of Metal rubber???

It took seven years of research,study. Polymer chemists have created a flexible, indestructible material, called metal rubber, that can be heated, frozen, washed or doused with jet fuel, and still retain its electricity-conducting properties. To make metal rubber, chemists and engineers use a process called self-assembly. The material is repeatedly dipped into positively charged and negatively charged solutions. The positive and negative charges bond, forming layers that conduct electricity. Uses of metal rubber include bendy, electrically charged aircraft wings, artificial muscles and wearable computers.