because there are ions in it the same way -

电流会通过凝胶同样--
for the same reason you don't drop an electrical device into the bathtub

因为同样的原因你不会把电器扔进浴缸里
because charge moves through water that has ions in it.

因为水里也有离子所以水可以导电
Charge is going to move through this gel and DNA is charged.

电流会通过凝胶而DNA是带有电荷的
It's loaded with phosphates which are negatively charged.

DNA分子上有很多带负电荷的磷酸根
They're going to move from a negative pole to a positive pole,

它们会从负极移向正极
so they're going to move through this gel.

会通过这块凝胶板
Well if you've created fragments here and they're fragments of different size,

如果你制造了一些长短不同的片段
the small ones are going to move faster than the big ones.

那小片段会比大片段移动得快一些
So the DNA is going to get spread out

因此DNA会根据大小
on this gel according to size,

在凝胶上分散开
with the small ones going farther and the large ones not going as far.

小的片段会快一些大的片段不那么快