When we do that, we often talk about the net velocity, or how fast a sample of gas moves from one place to another, like the rotten egg smell wafting its way to my nose.

当我们这样做时， 我们经常谈论净速度，或者气体样本从一个地方移动到另一个地方的速度有多快， 就像臭鸡蛋的气味飘到我的鼻子里。

The net velocity of a gas in any one direction will always be lower than the average velocity of its molecules because the overall motion of the gas is hindered by collisions among the individual particles.

气体在任何一个方向上的净速度总是低于其分子的平均速度，因为气体的整体运动受到单个粒子之间碰撞的阻碍。

If you listened carefully, you learned the difference between the net velocity of a gas and the average velocity of its particles, and that both things have a lot to do with the mass and kinetic energy of the particles.

如果你仔细听，你就会了解到气体的净速度与其粒子的平均速度之间的差异， 并且这两者都与粒子的质量和动能有很大关系。