器材:废磁带长120～180mm、一小段白色塑料膜(或废磁带头上白色的部分)、小丝线长约100mm、大培养皿(或小碟子)一件、防水胶、磁铁等。 方法(1) 将废磁带折成4～6层,并用防水胶粘上,用一块磁铁顺着一个方向摩擦这段废磁带约30次,使其磁化。把磁带放在大培养皿(或小碟子)内,皿内注入水(周围应无磁体或磁性物质),于是磁带被浮起,此时,可看到磁带在水面上慢慢地自 Equipment: waste tape length 120 ~ 180mm, a small piece of white plastic film (or scrap tape on the white part), a small thread about 100mm, a large Petri dish (or a small plate), waterproof plastic, magnets and so on. Method (1) The waste tape folded into 4 to 6 layers, and with waterproof glue, with a magnet along one direction rubbing the waste tape about 30 times to magnetize. Place the tape in a large Petri dish (or small dish) and fill the dish with water (no magnet or magnetic material around) and the tape is lifted. At this point, you can see the tape slowly on the water surface