There are numerous resources that can assist in your preparation for the big day. There are books. There are websites. And of course, there is The Physics Classroom's ACT Test Center. But of all the resources that you could look at, the one resource that you should spend at least a little time perusing is the ACT Student Website found at http://www.actstudent.org/. Consider the following two resources as part of your preparation:
The student section of the ACT website includes a collection of resources regarding the test, test preparation and test registration. The TestPrep section of the website will be of particular interest to students preparing for the ACT test. In addition to the purchase of a CD, this section provides seven sample science passages prepared by the ACT. The passage, questions and feedback are available. A Question of the Day feature is available. There is also an 80-page PDF document that describes how to prepare for the ACT test. The discussion includes not just preparation for the science test, but for all tests that the ACT offers. Test tips and test descriptions are also provided online. If you're serious about obtaining the best score you can score on the ACT test, then you owe it to yourself to make a visit to ACT's student website.
The ACT Student Blog is a blog written by students for students. The blog features short articles written by a collection of six students (two juniors, two seniors and two graduates). The blog is saturated with advice on everything from managing your school work, to relieving stress from your life, to preparing for and performing well on the ACT test. You will enjoy the advice given by these student experts. It's worth at least a visit.