For the average high school student, the science requirements
consist of one of the following sequences:
9th grade- Biology; 10th grade-
Chemistry; 11th grade-Physics
or
9th grade-Earth Science; 10th grade-
Biology; 11th grade- Chemistry; 12th grade- Physics
The original order was developed because educators thought
it was the easiest way to teach science. Each course requires successively more
difficult mathematics. Students could learn Biology more easily than Chemistry or Physics.