Over the last several years, many districts across the U.S. have adopted a "Physics First" sequence for their high school science. More traditional scope and sequence adoptions suggest physics to be an 11th or 12th grade science course, if taken at all. The sequence of biology, chemistry, and physics originally grew from an idea in the late 19th century. At that time, biology was about the organism---no DNA, genetics, viruses, and so on---a very naturalist approach. It made sense to have the "simpler" science first. But over the last 100 years, the field of biology has grown significantly. Students need a good foundation in basic chemistry to get the most from biology.
In a Physics First world, the idea is for kids to get a basic understanding of forces...so that they can make better sense of atomic bonding when they take chemistry...and then DNA when they reach biology. Many schools have spent a lot of time and money to retrain teachers and reverse the sequence. The San Diego School District had been one of these, but their school board recently voted to change the policy, even though the numbers of students in their science program has risen dramatically since adopting a "Physics First" program. The district continues to perform poorly on state tests in science and many students are struggling with the math component of a physics first world.
It is a difficult line for districts to walk: you have to get kids to standards but somehow consider the aptitude and personal interests of students in course development. I am wondering how many districts are going to follow San Diego's example. I'm sure that the "Physics First" curriculum has taught them all about pendulums...and it looks like this one is starting to swing the other way.