Here's a great essay Harold Pratt from Education Week in which he pinpoints some reasons and ways to improve science ed. in the elementary classrooms. The most important is problem-solving. There are so many jobs available today that didn't even exist when I was in elementary school. Who knows what it will be like when kids today are out there in the job market? They need to know how to question and analyze and figure things out on their own. That's it: we don't need to just teach them stuff, but how to figure stuff out.