Science is only on the ACT. However the SAT English usually has a passage of science-lit where they ask questions about whatever science the passage talks about.
Basically on the SAT, after about the 1400 range your score is pure luck of whether the questions happened to ask about vocab words / math formulas that you know or not. The essays are graded using who-knows-what criteria; they ask you a silly question and then dock you for any inability to overcome its silliness. My essays on the SAT, ACT and GRE have been given fairly mediocre scores; after all they have no way of knowing that I am a professional writer with a dossier of about ~40 student newspaper columns, ~30 magazine pieces and ~25 classical CD reviews published in an online daily, only that I wrote essays which answer the question as efficiently as possible without betraying too copiously my contempt for the abstruse blandness of the question.