Most high schools offer two main types of honors courses: regular honors classes and Advanced Placement or AP classes. A regular honors course is designed to challenge and stimulate more advanced students and the curriculum is determined by your teacher or school. Many high schools offer parallel honors courses for every regular science class in the curriculum. As of 2011, AP offers science exams in Biology, Chemistry, Environmental Science and Physics (three different areas). An AP course is structured to prepare you to take the AP exam in that subject. If you receive a high enough score on the AP exam (generally 3, 4 or 5 out of 5), you can receive college credit for that course.
Most college admissions offices look favorably on honors and AP courses. Because these classes are designed to be more challenging than the regular high school curriculum, an honors course on your transcript shows that you are willing to work hard and want to be challenged academically. In an honors or AP science course, you will probably get more experience with advanced research such as conducting experiments and dissection as well as writing about your endeavors. Also, if you plan to major in science in college, receiving AP credit can help you start on your major before you even attend college; regular honors science classes will help prepare you for the kind of work you may do in a college science class.
At many high schools, AP courses and honors courses carry a weighted GPA. This means that if you take that class, your GPA will be increased above the actual grade you earned to reflect the difficulty of the course. For example, if you receive a B in the honors course, points might be added to your GPA as if you had received an A- or an A. Check with your high school guidance counselor to find out your school's policy on weighted GPAs for honors courses.
High school honors and AP classes are usually smaller than the regular tracks. In a science class, this means you may have opportunities that you would not have in the regular courses. For example, you might do more experiments, or have full use, during class time, of lab equipment that students might have to share in a larger class. A small honors science class might also be able to take field trips to do research or use equipment that is not available on campus.
If you are making good grades in regular high school science courses, it's likely that your guidance counselor may suggest that you switch to honors classes. However, honors and AP courses often carry a much heavier workload than regular classes. You should make sure that you have enough time to accomplish everything. If you are already taking honors or AP courses in other subjects and want to add science, you might consider dropping to the regular level in another class so you don't feel overwhelmed.