pLuvia said:
There's also Earth and Environmental Science
But that's not very popular
And what Tennille says is true if you choose Senior Science you can't do any of the other sciences
Actually that's not completely accurate, you can't do preliminary Senior Science with any other preliminary science however you can pick up Senior Science in addition to another science subject in year 12. I'm not sure why anyone would want to do that but there you go.
I suppose Cosmology and Agriculture are also science subjects too, though I'm fairly sure neither are considered under the science category for the purposes of gaining a HSC.
As for the original topic: I did the three more popular science subjects and I honestly don't think its worth it, you do get some limited insight into how a science degree would be at uni but really the HSC is a chance to study whatever you want for the heck of it. Before the HSC, choice is so restricted and at uni many people do subjects for the sake of jobs at the end of it so I'd advise you not to waste this chance.
Also, its not worth doing all of the sciences for UAI purposes, people do better when they're in subjects they enjoy and are talented in rather than ones that scale well ... and the sciences don't scale
that well.