We’re guessing you didn’t sign up to take the SAT II just for the sheer pleasure of it. You probably want to get into college and know that the only reason for taking this test is that colleges want or require you to do so.

Colleges care about SAT II Subject Tests for two reasons. First, the tests demonstrate your interest, knowledge, and skill in specific subjects. Second, because SAT II tests are standardized, they show how your knowledge of Chemistry (or History or Math) measures up to that of high school students nationwide. The grades you get in high school don’t offer such a measurement to colleges: some high schools are more difficult than others, and students of equal ability might receive different grades, even in classes with a relatively similar curriculum.

When it comes down to it, colleges like the SAT IIs because the tests make the colleges’ job easier. SAT II tests allow colleges to easily compare you to other applicants and provide you with an excellent chance to shine. If you got a 93% on your Chemistry final and a student at another high school across the country got a 91%, colleges don’t know how to compare the two grades. They don’t know whose class was harder or whose teacher was a tougher grader. But if you get a 720 on the SAT II Chemistry and that other kid gets a 650, colleges will recognize the difference in your scores.

Occasionally, colleges use SAT II tests to determine placement. For example, if you do very well on the SAT II Chemistry, you might be exempted from a basic science class. It’s worth finding out whether the colleges you’re applying to use the SAT II tests for this purpose.