The principle underlying the working of the extravagant Noise- Cancelling headphones is, to put in a crude way 1+(-1)=0.
When two waves ( say, sound ) interfere with each other in such a way that the first wave cancels out the second wave, we call it Destructive Interference. When two waves destructively interfere with each other, we get silence! ( because the crest of the first wave cancels out the trough of the second wave and so on and so forth )
Noise- Cancelling Headphones.
Here is where it gets really interesting!
The primary function of a Noise-cancelling Headphone is to kill the ambient sound. A microphone records the ambient sound which is relayed to the speaker. The speaker produces a “destructive wave” which kills the ambient noise.
This leaves us with only the enchanted drug for the soul – Music, which gives a soul to the universe, wings to the mind, flight to the imagination and life to everything. – Plato.
Water is blue if you are talking about the water present in oceans, lakes and even your bathtub!
This is because red, orange and yellow (long wavelength light) are absorbed more strongly by water than is blue (short wavelength light). So when white light from the sun enters the ocean, it is mostly the blue that gets returned.
The hue of the sky (Azure) also contributes to the color of water.
The above phenomenon is predominant only when the depth of the water is about 1 meter.
This is why if you pour water into glass, it does not appear blue. It is colorless!
The color of water can also be altered by the particles present in water. For instance, presence of algae in water gives water a greenish color.
While high concentrations of dissolved lime gives it a torquoise color.
In extreme scenarios, water is seen to be in red and black in color.
So, what is the color of water you ask ? For all intents and purposes for everyday conversation, considering the magnitude of water present in Oceans, Seas, and Lakes, I guess it is safe to consider the color of water, as Blue!
Using paint is not the only way to mix colors. Overlap spotlights in a dark room and you get this:
Mixing red and blue gives pink ? What kind of sorcery is this? This is known as Additive color mixing and It’s very easy to understand.
An apple is red because all the other wavelengths of light which fall on the apple are either absorbed or scattered and the only color that reaches your eyes is red.
Now that you understand how color perception works. Let’s mix two colored lights, say blue and red. The reason why you see pink is because when both blue and red light reaches your eyes simultaneously, the red and blue cone cells fire up and the translates the resultant color as pink.
It gets even better!
Although technically white is the combination of all wavelengths of light in the visible region, here’s the deal. To us humans, we don’t need the infinite wavelengths of light to see white. Mere blue, red and green is sufficient. This has to do with the fact that humans are trichromatic!
Looks like the human body is much more intricate than i had marveled!
An exotic new state of matter – Transparent aluminium.
Yup, you heard it right! And No! this is not a star trek reference
Oxford scientists in 2009 bombarded aluminium with the most powerful soft X-ray laser. They focused all this power down into a spot with a diameter less than a twentieth of the width of a human hair. At such high intensities, aluminium turned transparent.
The invisible effect lasted for only an extremely brief period of time- an estimated 40 femto-seconds. But hey! The existence of such an exotic state of matter per se, opens up new frontiers for pristine research and technology. As Albert Einstein rightly said:
The process of a scientific discovery is, in effect, a continual flight from wonder.