The interesting facts about magnets
"The loving stone" - such poetic name was given by Chinese to the natural magnet. The loving stone (tshu-sh) – Chinese say – attracts iron as gentle mother attracts the children.
It is remarkable that at the French (the people living on the opposite end of the Old World) we meet the similar name for the magnet: the franyotsuzsky word "aimant" means both "magnet", and "loving". The power of this "love" at natural magnets is insignificant and therefore the Greek name of the magnet — "the Herculean stone" very fondly sounds. If inhabitants of ancient Hellas so were surprised the moderate attractive force of the natural magnet, that they would tell, having seen the magnets lifting blocks in the whole tons at modern steel works is powerful! However, it is not natural magnets, but electromagnets, i.e. the iron masses magnetized by the electric current passing on the winding surrounding them. But in both cases force of the same nature — magnetism works.
It is not necessary to think that the magnet affects only iron. There is some other bodies which are influenced by action of the strong magnet too, though not in such degree as iron. In weak degree such metals as nickel, cobalt, manganese, platinum, gold, silver, aluminum are attracted by the magnet. Even more remarkably than property of so-called diamagnetic bodies, for example zinc, lead, sulfur, bismuth: these bodies make a start from the strong magnet!
Liquids and gases are also influenced by the attraction or pushing away of the magnet, however, in very weak degree; the magnet has to be very strong to show the influence on these substances.
Pure oxygen, for example, парамагнитен, i.e. is attracted by the magnet; if to fill with oxygen the soap bubble and to place it between poles of the strong electromagnet, the bubble will considerably be extended from one pole to another, stretched by invisible magnetic forces. The candle flame between the ends of the strong magnet changes the normal form, obviously finding sensitivity to magnetic forces (fig. 1).
Task about the compass
We got used to think that the arrow of the compass is always turned by one end on the North, to others — on the South. The following question will seem to us therefore absolutely silly:
Where on the globe does the magnetic needle show on the North both ends?
Also the question will even more ridiculously sound:
Where on the globe does the magnetic needle both ends show on the South?
You are ready to claim that there are no similar places on our planet and cannot be. However they sushchestyovut.
Remember that magnetic poles of Earth do not match its geographical poles — and you probably Yodogadayetes about what places of our planet there is in the task the speech. Where will the arrow of the compass placed on the South geographical Pole show? One its end will be directed towards the next magnetic pole, another — in opposite. But to whatever party to go from the South geographical Pole, we will always go to the North; there is no other direction from the South geographical Pole - around it the seyover everywhere. Means, the magnetic needle placed there will show the North both ends.
In the same way the arrow of the compass postponed for the North geographical Pole both ends has to show on the South.