Cheat Dice

[TimeSpaceLightForce]

 

                                     

Three of the above  standard dice of know weight has a magnet pip on center of one side.
These cheat dice  weigh normally when measured on top of the throwing table with induced magnetic 
field but would be 1 unit heavier or lighter when the magnet pip is facing  (parallel with) the table.
With  balance scale  and/or weighing scale available..what is the best method  to sort out the fair die.

[jasen]

put 1 dice at the right side and 1 dice at the left of a ballance scale.
after several times changing different side of the dices, 
we can find the normal weight.

then let the left dice as standard.
then weight other three dices, each side once.
if a dice show anomally (get heavier/lighter) when the side changed,it must be cheat dice.
if we find 1 dice without anomally then it is the true dice.

if all 3 dices is not true dice, so the left dice which we use as standard is the true dice.

Edited November 2, 2015 by jasen

[TimeSpaceLightForce]

@jasen..nice start

Note that a cheat die may have the center magnet pip on its 1 or 3 or 5 , since the polarity of magnet's exposed side  is either (+) or (-), the opposite sides 6 or 4 or 2 can be heavier or lighter too. Thus there are just 3 ways to test the N / H / L weight of the die. 

Your procedure mostly  can try the 1st right die x3 tests,the 2nd right die x3 test,the 3rd right die x3 test.
Or total of 9  tries. Same with a weighing scale : 1st die- N,N,H/L   2nd die-N,N,H/L  3rd-N,N,H/L. Luck aside.

Surely the no of trials can be lessen..