Difference in PH Science Explorer publication dates

[ballzy]

I am considering PH Science Explorer for my ds who will be in grade 7 next year. I am wondering if I should get a used set that is copyright 2000 or spend the money to get the most recent versions. I have 3 more dss (9y,6y, and 20 months)who could use the books in the future. My 2nd ds would be ready to use the series in 2-3 years, and my 3rd ds would be ready in about 6 years (if I start them when they are in grade 7).

Also, other than the text books, what other things in the series would be good to have?

Thanks.

Colleen

[LisaNY]

We're currently using Earth's Waters - copyright 2000. I see no reason to have a newer version. It is an excellent text, and we've learned a lot.