These are two great responses, but they seem to be saying opposite things.<p><a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10877128" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10877128</a> <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10877121" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10877121</a><p>One says electrons bump into electrons, the other says electrons bump into non-charge-carriers. Someone on Twitter said it was phonons.<p>I guess I can kind of imagine a pachinko machine, but this is all very unsatisfying. :-)<p>Edit: From the Wikipedia link: &quot;Charged particles in an electric circuit are accelerated by an electric field but give up some of their kinetic energy each time they collide with an ion&quot;<p>I mean, electrons are very very lightweight and tend to move quite slowly for typical currents. How much kinetic energy can they give?