I questioned the longer gaps as well. I'm not sure how well a student would remember their observations and ideas from 1st grade when they finally come back to it in 4th grade, this is all assuming that it is actually done in the earlier grades.
The idea of going deeply in high school has me excited, but scared. There are many students that aren't interested in the sciences, and I wonder how this will play out with graduation requirements, college and career readiness, as well as the drop out rate. Currently, there are only 2 credits required for HS graduation in science. This is usually in the form of a general Physical science and biology. Will the additional science standards increase the drop out rate?