When I was in high school, back in the 1950s, it was very popular for high school students to have gel - a type of gel in their hair. 上世纪50年代，我中学的时候，中学生很喜欢用凝胶，一种发胶。

Maybe one of the more famous movies in the United States about 1950s and 1960s in high school was called Grease, "Grease." 也许在20世纪50到60年代，美国中学生中最著名的电影之一就是《油脂(Grease)》。

And in Grease, which starred, I think, Olivia Newton-John and John Travolta - I'm not sure, I, 《油脂》的主演，我记得是奥莉维亚·纽顿-约翰和约翰·特拉沃尔塔，不太确定。

as a man, have not watched it as much as most American girls and women have - 我是男孩子，不像美国女孩子那么喜欢看。

but in the movie, I remember that the boys had gel - a type of gel on their hair to make it very flat on their head. 不过我记得，这部电影里，男孩子们喜欢用凝胶，就是一种可以让头发服帖的发胶。

Getting back to Lucy, she says that she "put a little gel in" her "hair to give it some" extra "volume." 回到露西，她说她“往头发上抹了点发胶，让头发看起来更丰盈”。

Volume, "volume," means she made it thicker, or fuller, or bigger. 丰盈(Volume)，意思是她让头发更厚，更饱满，更蓬松。

To add volume to your hair means to make it thicker. 让头发看起来更丰盈意味着使头发变厚。