As of March 2016, the ACT science section no longer has 7 passages – it now has just 6 longer passages. (If you’d like to learn subtleties and focus of the different passage types, please contact me for a session.)
The SAT does not have a science section.
Science content is relegated to reading comprehension. To compete with the ACT, The SAT weighs SUBTOPICS of questions within the English/reading or math sections –which are actually science, history or social studies questions– towards a 40 point “cross-test” score.
As of April of 2017, Illinois public schools have purchased the SAT as the entrance exam of choice. This means that as of late April this year, public high schools will be offering the SAT instead of the Prairie State ACT.
As of March 2016, the ACT includes a STEM score. There are only slight changes of content. I can teach you content seen on ACT or SAT but rarely seen in classrooms.