Myth v/s Fact

Use of bonded rare earth metals: These are lower in cost toto manufacture. However as the magnet is only bounded, it's not that strong.

Physical Damage: A magnet separator is hit or dropped. It will affect its magnetic power.

Exposure to Heat: When rare earth metals are exposed to heat over 80 ° C. There is reduction in magnetic strength.

The Gravity in the Hudson Bay area and surrounding regions is lower than it is in other parts of the World, a phenomenon first identified in the 1960s. Scientists gave two theories to explain this effect.

The first theory is known as Convection Theory. Deep down earth, there is a layer of hot molten rock called Magma which keeps on shifting, rising, and falling which results in a decrease in mass of that area. And as gravity is proportional to mass, as a result, that area has less gravity.

Another theory is of Laurentide Ice sheet. This 3.2 Km thick Ice Sheet melted 10,000 years ago left an indentation on earth which decreased the mass of that portion of the earth and finally results in less gravity.

The north star is the star that is positioned right above the celestial pole which remains fixed as the earth rotates on its axis. thus showing true north.

But Polaris is not the brightest star in the night sky, not even 'close'. Polaris is about 50th in terms of brightness.

The brightest is Sirius, the dog star in the constellation of Canis major.

In nature it is difficult to hear a quack’s echo as the sound profile of the quack reflects less than other sounds in the surrounding environment, so the echo is comparatively low in amplitude and harder to detect.

Though a reverberation chamber can be used in order to amplify the echoes by providing a large enough aperture for the sound to be reflected.