Ck-12 is a resource that is attempting to provide a quality textbook or "flexbook" for any student who needs or wants one. Ck-12 began their mission over eleven years ago. Their mission began as a non-profit and non-revenue institution. This means they have never asked teachers for money or fund raising. Ck-12's purpose is to provide a high quality resource free to teachers and students. Teachers can use Ck-12 as long as the use is for educational purposes.
I started to use Ck-12 about five years ago. Our books were getting older. I was able to search for a book on Ck-12, change it, edit it slightly and then rename it. This is why these books are called "flexbooks". Teachers have a great amount of flexibility when it comes to editing, changing or rearranging a book to meet their own needs. Students can examine the books in multiple formats.
Ck-12 has constantly been in touch with teachers and students. The feedback from both groups has been used to help improve their products to meet the needs of students. Here are just a few of the ways that teachers might use Ck-12.
Flexbooks - Any teacher can search for a multitude of books. They can rename them, edit them, change the books, add or delete information and then publish them. Students and parents can then access these books in multiple formats.
Learning Management Systems - Ck-12 has created many opportunities to mesh their products with most learning management systems. A teacher can take all of a book or just bits and pieces and assign it to students through a wide variety of learning management systems.
English as a second language - Many teachers have taken advantage of Ck-12 as a tool to help students who speak a different language. A student can pull up a chapter in Ck-12 in English. The student pulls up the same chapter on a lap top. They can then translate one of the chapters into their own language with the click of a button. Students can then compare the two screens, one in English and one in a different language, to help them better understand the concept.
Differentiation - Ck-12 provides a multitude of resources (readings, videos, simulations...) for different concepts. If some students struggle a bit more with reading, then they can have the option to examine a video or simulation over the same topic.
A Panel of Experts - All of the material has been examined by scientists, professionals and teachers. No book or resource is perfect but Ck-12 is close. Teachers encourage students to search for a topic in Ck-12 instead of Google. The Ck-12 search generally tends to be vetted by professionals and more specific to student needs.
Adaptive Practice - This is probably my favorite part of Ck-12. You, as a teacher, can provide some "practice" problems. Students must get ten correct. The questions are from a bank and are "easy", "medium" or "hard" questions. Suppose two students, "A" and "B" start with the practice. They both start with two to three "easy" questions. Suppose student "A" gets them correct. He or she will then start getting "medium" questions and then "hard" depending on how he or she answers the questions. Next, student "B" misses the first three easy questions. Ck-12 will stop them and provide resources. These resources are there to help the students better master the topic. Student "B" will then resume with some easy questions. The teacher receives a full report when each student is finished. The "adaptive practice" is a type of differentiation for every student.
Notes and Annotations - Students have the option of taking notes and high-lighting assigned readings online. The notes and annotations are then stored for them at the bottom of the section. This can help students with note taking and reviews.
This is just the tip of the iceberg. Ck-12 is a free resource that is definitely worth checking out.