ends outrue. that's right. that's what it is. yeah, alpha particles, slowed down. yeah. - yeah, really? - yeah, really. yeah. it turns out whenhat warm air rises-- and it rises, by the way, because--i didn't mention that. itises because it's in migrations. every time it happens to be going down, does it see a lot of atoms a little bit? a lot to bounce off. when it happens to be going up, does it see a lot or a little? not quitso many as down. so when it's banging-- [makes sound] won't it finally bumble to the regions of less pressure? and then go a little further-- [makes sound] bounce and comes back down, there's more underneath. so zillions and zillions bounces per second, you know, [mes sound] find its way right to the top. just like you had a whole lot of people in the room and they're all dancing around to something and they're all crowed to one end of the room and you put some drunk in the middle who moves faster than anyone se. [laughter] and that drunk is out of it and you wanna go find that drunk-- and you look in the part of the room with a very, very few