Which is magnet?

You have two similar looking bars of iron. One is a magnet, and the otherone is not. Without using any other instrument (thread, filings, other magnets, etc.), find out which is which?

Answer:

Take the two bars, A and B and put them together like in the shape of the letter 'T'. A being horizontal and B standing vertically and bisecting A. If they stick together, then bar B is the magnet. If they don't, barA is the magnet. REASON: Bar magnets are "dead" in their centres (i.e. there is no magnetic force, since the two poles cancel out). So if bar A is the magnet, then bar B won't stick to its center. However, bar magnets are quite "alive" at their edges (i.e. the magnetic force is concentrated). So, if bar B is the magnet, then barA will stick nicely to its end.