Access our award-winning, free resources for teaching and learning science.

About us

We create and provide high-quality, accessible, educational content in the science, technology, engineering and mathematics (STEM) disciplines at the introductory undergraduate level.

Learn More
We support NGSS

Our exclusive content integrates science and engineering practices with disciplinary core ideas and cross-cutting concepts in alignment with the Next Generation Science Standards.

Learn More

Quick Quiz

Earth's magnetic field is constant.

Go to Quiz

Module of the day

Uncertainty, Error, and Confidence

There is uncertainty in all scientific data, and even the best scientists find some degree of error in their measurements. This…

Go to module

Term of the day

average

[noun] In statistics, average commonly refers to the arithmetic mean, also called simply "mean," which is one measure of the mid-point of…

Go to term