问题：两根外形完全相同的钢棒，已知其中一根有磁性，另一根没有磁性．怎样判断哪一根有磁性？解析：此题考查了磁极的概念和磁极间相互作用的规律，考查了同学们对磁极问题的理解程度．一般条形磁铁的磁极在棒的两端，棒中间的磁性很弱．可以利用磁极的性质和特点来判断．方 Problem: Two identically shaped steel rods, one of which is known to be magnetic and the other one is not magnetic. How to determine which one is magnetic? Analysis: This question examines the concept of magnetic poles and the interaction between magnetic poles, and examines students’ understanding of magnetic pole problems. The magnetic pole of a general bar magnet is at both ends of the bar, and the magnetic force in the middle of the bar is very weak. You can use magnetic poles to determine the nature and characteristics. square