Pull up the California Standards for Public Schools on the Internet. The CST is based on the state teaching standards. The standards are divided into grades, then subjects. The science portion is divided into biology, chemistry, physics, and life sciences.
Look at your child's science textbook. Make sure her textbook covers what is in the teaching standards. For example, if she is taking biology, check the biology teaching standards to make sure all areas are in the textbook. These will be the areas covered on the biology section on the CST. Your child will only be tested on the science subject she is taking at the time. If she has not taken chemistry, she will not be tested on chemistry.
Inquire about remedial classes or tutoring if your child has scored low on the high school science portion of the CST. Some schools offer remedial classes and tutoring to bring up a child's score. If yours does not, you can call a tutoring center to see if it offers tutoring for high school science for the CST.
Log onto the Internet website that offers practice for the CST. The online practice test is divided into grade level and subject. Twenty-five percent of each year's test is online for practice.