Magnet and iron rod

[Sensei]

If you are provided with 1 iron rod and 1 magnet rod both equal in size weight and colour then how will you find out which one is magnet and which one is iron?

 

I guess so this question is not full? What devices or things we can use during testing.. ?

 

If I will rub magnet on needle, needle will become magnet (one rub in one direction is enough for mine needles). Then you can carefully place needle on water in glass, and it'll be pointing north-south direction, or point to the nearest strongest magnet.

 

If I will rub iron on needle, nothing will happen. Needle won't change to magnet.

 

Another test with f.e. aluminum pipe with enough hole placed vertically.

Iron will pass through pipe at pretty normal speed and time.

Magnet will be passing through pipe significantly longer (20 times longer in mine test).

 

I have 2 meters long aluminum pipe with diameter 12 mm and 10mm diameter of hole, 1mm thickness of metal.

Strong neodymium magnet (8mm diameter, 3mm height) will pass through it in 12-13 seconds. That's 20 times longer than other items than magnet.

When I stacked 3 such magnets, time increased to 19 seconds.

Items made of aluminum or iron with similar size to magnet are passing through it in 0.63 seconds approximately (too fast to count precisely using stopper, so used d=1/2*a*t^2 equation t=sqrt(2*2/9.81)=0.63 s)

[Trumptor]

Whack yourself in the head with each bar really hard. Then, starting with the bar in your right hand say, "eenie meenie miney mo catch a tiger by the toe, if he hollers let him go, eenie meenie miney mo" and the one that "mo" lands on is the magnet.

[John Cuthber]

 

I guess so this question is not full? What devices or things we can use during testing.. ?

 

If I will rub magnet on needle, needle will become magnet (one rub in one direction is enough for mine needles). Then you can carefully place needle on water in glass, and it'll be pointing north-south direction, or point to the nearest strongest magnet.

 

If I will rub iron on needle, nothing will happen. Needle won't change to magnet.

 

Another test with f.e. aluminum pipe with enough hole placed vertically.

Iron will pass through pipe at pretty normal speed and time.

Magnet will be passing through pipe significantly longer (20 times longer in mine test).

 

I have 2 meters long aluminum pipe with diameter 12 mm and 10mm diameter of hole, 1mm thickness of metal.

Strong neodymium magnet (8mm diameter, 3mm height) will pass through it in 12-13 seconds. That's 20 times longer than other items than magnet.

When I stacked 3 such magnets, time increased to 19 seconds.

Items made of aluminum or iron with similar size to magnet are passing through it in 0.63 seconds approximately (too fast to count precisely using stopper, so used d=1/2*a*t^2 equation t=sqrt(2*2/9.81)=0.63 s)

You didn't guess correctly.

The question is complete.

You are not allowed to use anything else. No iron filings and bits of paper, no needles and glasses of water. Just the two bits of metal.

The classic form of the puzzle relies on the idea that the magnet is magnetised so that one end is a North pole and the other end is South.

That's the most common configuration, but it's not the only possible one.

For that simple configuration the test is easy (and has already been described).

For other possible configurations of magnetisation, it may or may not work.