Science & Mathematics Questions & Answers

Sea cucumbers are echinoderms that have a tough leathery skin rather than a spiny one. Lying around on the sea floor in tropical and subtropical countries they look rather like long fat sausages with tentacles at one end. They feed by poking the sticky tentacles around and then placing them one by one into the mouth. All the food fragments …

Every now and then we hear of countries of the world carrying out heated discussions about nuclear bombs. The topics range from who has the right to own a nuclear bomb and who does not, who should use it and who must not and so on. But what exactly happens when such a bomb actually explodes? And how are nuclear …

There is a little motor fitted in a cell phone. This motor has unbalanced weight, in other words, is unevenly weighted on its output shaft. When this motor rotates, the rotating uneven weight causes the mobile to vibrate. A similar mechanism is also present in gaming devices such as the play station.

Mobile phone tracking relies on the use of triangulation – taking signal strengths registered from the mobile phone at a minimum of three nearby GSM receiver masts. As the mobile phone companies know the position of each mast, and can tell the signal strength of your phone at each of these nearby masts, they can use this to calculate the …

A mirage is a kind of optical illusion that occurs in hot, still weather. A pool of water suddenly appears in the distance. But on approaching, it seems to evaporate and there’s actually no water at all. You may see these mirages on roads in summer. They also occur in deserts, sometimes complete with trees, and may trick a thirsty …

When you bring a magnet close to another metal object such as a nail, the nail will be attracted towards it. This power of attraction is created by lines of force which surround the magnet. They cannot be seen, but if you place a thin sheet of paper over a magnet, and scatter iron filings on the upper side of …

A laser mouse is a type of optical mouse. It uses a laser beam which is invisible, or nearly invisible, to the human eye. The beam emitted by the laser mouse moves with the user’s hand, triggering an optical sensor system. It works in tandem with a system which tracks how far the mouse has moved by bouncing hundreds of …

Each of the vertebral bones in the spine is separated from the next by a thick and pad of fibrous tissue. The pad is roughly disc shaped and has a soft center. If the tissue is damaged, the soft center can bulge out to squeeze a nerve and so cause pain.

The cryogenic engine gets its name from the extremely cold temperature at which liquid nitrogen is stored. Air moving around the vehicle is used to heat liquid nitrogen to a boil. Once it boils, it turns to gas in the same way that heated water forms steam in a steam engine. A rocket like the Ariane 5 uses oxygen and …

The tip of a ballpoint pen, the part that writes, is very tiny metal ball in a socket. As you write, the ball spins, so that the ink is put evenly on to the paper. The side of the ball which you can’t see is in contact with the cylinder which holds the ink, so that ink always moves evenly …