The non-profit CK-12 Foundation offers free STEM activities through digital textbooks in science, technology, engineering, and mathematics subjects (STEM!). CK-12 aligns with state standards. These digital textbooks are available for download on your computer, iPad, Kindle, or other compatible e-reader.
Here’s a video explaining the CK-12 Study Guides better than I can:
Get the free STEM activities :
All of the CK-12 are Kindle- or eReader- ready and available for immediate download at the Kindle store, here. Most of them are free!
Looking for free STEM curriculum?
I’ve highlighted and reviewed these: