Mr. Robinson has some great methods and techniques that obviously work well for a lot of people. Our methods also work well for a lot of people. Our methods stem from a fundamental idea that mathematics is considered by many as "the language of science." So, to learn the language of math well, you do science along the way. And to learn science well, you learn math along the way. It's not an "either/or" thing, but a "both/and" thing. And, of course, I'm not saying the Robinson curriculum opposes "both/and" learning of math and science, just that maybe we emphasize that more and Robinson curriculum emphasizes it less.
So, along those lines, we have an Algebra 1-level science course called Integrated Chemistry and Physics that teaches physics and chemistry fundamentals, to be used later on in the full Chemistry and Physics courses we offer. This also gives students some chemistry and physics background that is helpful for Biology. After biology, we recommend Chemistry, followed by Physics. Math in Chemistry is more Algebra 2 level, and math in Physics is more Precalculus level, which is why we have them ordered the way we do. We have lots of students who go on to do amazing things in science and engineering, as I'm sure Robinson Curriculum users do as well.