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Curriculum Products
Categories: Math and Science
CK-12 PlatformCK-12 Platform
CK-12 Platform
by The CK-12 Foundation
GRADES / Elementary (Grades K-4), Middle School (Grades 5-8), High School (Grades 9-12), Higher Education
PLATFORMS / Web Browser, iOS Devices, iPad, Android, Windows

Provider of open-source STEM content; allows teachers to compile and share custom digital textbooks


CK-12 is an online educational content site sponsored by the CK-12 Foundation, a nonprofit that desires to increase worldwide K-12 access to high-quality STEM content. CK-12’s main offering is a collection of free digital textbooks (called “Flexbooks”) for high school age students, particularly on topics in science, engineering and math. As of September 2013, CK-12 has created a total of 88 Flexbooks that cover approximately 5,000 STEM content areas (from life science, like DNA vs. RNA, to sequences and series in calculus).

CK-12 offers far more than just textbooks on a screen, however. It’s giving the word “remix” real meaning in education. In addition to traditional text-based material, CK-12’s material is available in more than a dozen other modalities, such as videos, quizzes, flashcards, and “simulations,” or interactive content that brings visualization to abstract concepts. For example, a simulation of force might be showcased with an interactive Ferris wheel, which the user can click on and move to manipulative a force tracker.

What’s more, CK-12 is also creating a collection of tools that enable teachers, students or subject-matter experts to either add additional material or create material from scratch. In basic terms, users can assemble CK-12’s material according to their needs. For instance, say a high school biology teacher wants to create the equivalent of a workbook around the skeletal system, but hopes to create a balance between text and visual information. The teacher could pull from the “Human Skeletal System” content collection, specifically selecting the written text, a video overview of the skeletal system, and a link to an interactive virtual body website. The teacher can also add to or remove information from the textual component, depending on how surface-level or in-depth he or she wishes to go with their students.

When teachers or students visit the CK-12 website, they can search for Flexbooks according to their needs without logging in. Users also have access to CK-12’s other platforms, specifically Braingenie (a collection of fast-pitched K-12 math and science question), I Need a Pencil (free online SAT preparation), and FlexMath (a collection of math tools and assessments).

CK-12’s products are free for anyone across the globe, and available in over 70 languages. However, while teachers and students do not need to register to use the CK-12 Flexbooks, those who do register will find additional tools and resources available for their use.

Registered students: Upon registering, students gain access to "StudyHELP," a space where students can engage in peer-to-peer learning; they can post questions about content, form study groups, and establish connections with other students.

Additionally, registered students have access to a student dashboard, a space where they can organize CK-12 content for their use. Revamped in September 2013, CK-12’s student dashboard includes the ability to self-study with assessments attached to each of CK-12’s over 5,000 concepts, and a group function, where students can form study groups for themselves and their friends, or join a class group created by a teacher.

Registered teachers: For teachers, the experience of logging into CK-12 includes a number tools that support the actual use and implementation of Flexbooks. Teacher who log in gain access to a dashboard where they can organize their own content by either using whole Flexbooks, readjusting those Flexbooks, or by combining their own added content with CK-12's existing content. Teachers can also use the dashboard to track their students' mastery of concepts, seen on the front page of the dashboard, with the aid of a quiz-making capability (see below). Additionally, the "Groups" function allows the teacher to create groups of students with whom they can share specific Flexbooks, give assignments to, and track both individual and aggregate performance (either via controlled "Class" groups, or those aforementioned "Study Groups," where any member can share content).


                                        CK-12 teacher dashboard student tracker.

Since its founding in 2007, CK-12’s user base has widened to include students in public, charter, and independent schools, with 75% of usage occurring in American schools while the remaining 25% occurs internationally (particularly in Asia). While 75 languages are currently represented on the site, CK-12’s content management team plans to add more.

Though CK-12 started out as a site that predominantly pushed online textbooks, CK-12 reps explain that the development of wider and more customizable content came out of the desire to reach various learning styles and allow teachers to design the best blended learning environments. As such, CK-12’s future endeavors include adding more and more content and modalities for teacher and student use. Most noticeable evidence of this is CK-12’s ever-growing collection of “simulations.” As of August 2013, the site had over 200 simulations.


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Summit Reflections 2
7th and 8th STEM teacher

I wish that it is advertised more. I learned that it has been around for 6 years, and this ...


CK12 FlexBook Overview
CK12 FlexBook Overview
Quick Start Guide
Quick Start Guide
CK-12 Flexbook Introduction
CK-12 Flexbook Introduction
CK-12 at the EdSurge Summit
CK-12 at the EdSurge Summit


7th and 8th STEM teacher

I wish that it is advertised more. I learned that it has been around for 6 years, and this ...

High School Math, Art, Life Skills Teacher




Common Core Aligned Common Core Aligned
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Lesson Planning Lesson Planning
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Supplemental Supplemental

Subject Matter

Algebra II and Trigonometry Algebra II and Trigonometry
Arithmetic Arithmetic
Biology Biology
Calculus Calculus
Chemistry Chemistry
Early Math Early Math
Earth Sciences Earth Sciences
Geometry Geometry
Math Math
Physics Physics
Pre-Algebra and Algebra Pre-Algebra and Algebra
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STEM Education STEM Education