Want personalized picks that fit your family?
Set preferences to see our top age-appropriate picks for your kids.
A lot or a little?
The parents' guide to what's in this website.
What parents need to know
Parents need to know that CK-12 is a website that offers a variety of free lessons in STEM subjects (Science, Technology, Engineering, and Math). The site breaks down traditional book chapters into smaller, bite-size ideas that may be easier for kids to digest. Although it's called CK-12, most of the available content is probably best suited to older kids and teens; many advanced subjects are covered. Information for younger kids also is on the site, but you may have to help them find it.
- Parents say
- Kids say
What's it about?
CK-12 is divided into three sections: Mathematics, Science, and More. Mathematics includes subjects from arithmetic to trigonometry and statistics. Science covers all the bases: biology, chemistry, and physics, as well as life, earth, and physical sciences. The More section offers history, technology, and economics. Within each subject, you can click on a circle to get even more specific; each contains a number of Concepts, which are short, chapter-like lessons. For example, if you click on \"phases of matter\" within the physical science section, you will be given a list of topics that include evaporation, sublimation, and solutions. Within those, you can choose from a series of modalities: read, study aids, video, or web links.
You can bookmark material you'd like to save for later, or you can send it to a classmate by email or social media. Kids can create groups to share content with each other. If you're looking for a very specific topic, enter it into the search box to go straight there.
Is it any good?
Material on the site is well organized and very accessible. CK-12 likely will appeal most to kids who are already fairly studious; it doesn't oversimplify ideas. Although it does cover simpler subjects like arithmetic, its presentation might be too advanced for kids of the appropriate age to understand on their own. It's perfect with a parent's help, however.
CK-12 is very committed to reaching kids with all types of learning styles, and the inclusion of video, audio, quizzes, and other tools may open doors for kids who are having trouble in the classroom. The site is essentially transforming a textbook into a multimedia experience, which is very exciting. There's another major bonus: all this content is free! And it's available in nearly 50 languages. Some subjects contain more content than others, but teachers are adding lessons all the time, and the site should continue to grow.
Talk to your kids about ...
You can talk with your kids about why it's important that both boys and girls learn about math and science. Explain that people haven't always believed this.
Many animated movies popular with kids feature detailed ecosystems, like A Bug's Life and Ice Age. When your kids watch these movies, point out those worlds and ask them to describe them.
- Subjects: Language & Reading: naming, reading
Math: arithmetic, geometry, statistics
Science: engineering, chemistry, ecosystems, physics, plants
Social Studies: cultural understanding, events, history
- Skills: Thinking & Reasoning: analyzing evidence, deduction, memorization
Creativity: combining knowledge
Self-Direction: academic development, identifying strengths and weaknesses, work to achieve goals
- Genre: Educational
- Topics: Science and Nature
- Price: Free
- Pricing structure: Free
Themes & Topics
Browse titles with similar subject matter.
For kids who love math and science
Common Sense Media's unbiased ratings are created by expert reviewers and aren't influenced by the product's creators or by any of our funders, affiliates, or partners.