We are a non-profit organization that connects students to real science and exploration to inspire and motivate them to study and pursue careers in Science, Technology, Engineering and Math (STEM) fields.
The Norton Field Guide to Writing is a much praised classic guide to writing, and has long been used in college level English courses. Their website contains much of the material in the original book, plus an online handbook, exercises, genre writing tips, and much more. It is an excellent resource for high school & college students, and even better now that it does not require any registration
CK-12 is a non-profit educational site that offers learning resources for core subjects (particularly math and the sciences) to students of all ages, through well-organized text lessons, audios, videos, interactive activities and tracking quizzes.