When a brief pulse of electricity is sent to the read/write head it flips on a tiny electromagnet for a fraction of a second.

当一个简单的电脉冲被送到读写头,它会短时间内出现一个小的电磁。

哈佛公开课 - 计算机科学课程节选

Because it's a gel electricity is going to move through the gel because there are ions in it the same way - for the same reason you don't drop an electrical device into the bathtub because charge moves through water that has ions in it.

由于凝胶中存在离子,电流会通过凝胶,同样--,因为同样的原因你不会把电器扔进浴缸里,因为水里也有离子,所以水可以导电

耶鲁公开课 - 生物医学工程探索课程节选