That is metallic sodium that would keep in kerosene so it doesn't react with the oxygen in the air.

金属钠应该保存在没有中,这样它就不会和空气中的氧气反应了。

麻省理工公开课 - 固态化学导论课程节选

Our piston on the right side here fully out, and the piston on my right side, your left side, fully inside. There's no gas p1 on that side here. So there's p2 sitting here.

左边的这个活塞完全在外面，而右边的左边的这个活塞完全在里面，这边没有一点空气,这边是P2，这边是。

麻省理工公开课 - 热力学与动力学课程节选