Since early 2016, Time4Learning has made Science4Us available as part of the Time4Learning curriculum.

For students, they access it by clicking on the big Science4Us button in their student dashboard.
Information for parents including printables of all of the hundreds of hands-on science materials, is accessed through the Parent Dashboard by clicking on Lesson Planning / Lesson Plans / Science4Us.

If you want more background information on Science4Us, I'd suggest watching the video on the Science4Us homeschool page: Homeschool

Are your kids using Science4Us? Any reactions? And for detailed discussions, there is also a Science4Us subforum on this forum.