Elementary (Grades K-6)

Open Wide and Trek Inside (Grades 1-2) - Free standards-based curriculum that focuses on the science of the oral environment, and major scientific concepts relating to oral health. (Publication No. 00-4869) (Office of Science Education and National Institute of Dental and Craniofacial Research )
http://science-education.nih.gov/customers.nsf/

Cells, Genes and Protein Machines Coloring Book - This coloring book is for children in grades 1 to 3. It is a story that teaches children that a gene, when active, makes a specific protein in the cells of the human body. When every cell type carries a full set of genes, each different type uses only the subset needed for its specific function. (National Cancer Institute)
https://cissecure.nci.nih.gov/ncipubs/details.asp?pid=1084

Milk Matters with Buddy Brush Coloring Book - 15-page coloring book designed to teach children ages 4-8 about the importance of milk. To view this PDF file you will need Adobe Reader, which you can download for free for either a PC or Macintosh.  (National Institute of Child Health and Human Development)
http://www.nichd.nih.gov/publications/pubs/upload/mm_with_buddy_brush_2006

NIEHS Classroom Activities for Scientists - Find simple strategies and activities that you can use effectively communicate complex ideas on toxicology to students. (National Institute of Environmental Health Sciences)
http://www.niehs.nih.gov/science-education/scientists/classroom.htm

The Great Escape Maze 1 - Print out a maze and help Bo make it to the Great Calcium Fair! To view this PDF file you will need Adobe Reader, which you can download for free for either a PC or Macintosh. (National Institute of Child Health and Human Development)
http://www.nichd.nih.gov/milk/kids/kidsteens.cfm

Middle School (Grades 7-8)

Chemicals, The Environment, and You: Explorations in Science and Human Health (Grades 7-8) - Free standards-based curriculum that focuses on the relationship between chemicals in the environment and human health, utilizing basic concepts in the science of toxicology. (Publication No. 00-4870) (National Institute of Environmental Health Sciences and Office of Science Education)
http://science.education.nih.gov/customers.nsf/MSEnvironment?OpenForm

Doing Science: The Process of Scientific Inquiry (Grades 7-8) - Free standards-based curriculum that explore the basics of scientific inquiry, refine their critical-thinking skills, and appreciate the purpose of scientific research. (Publication No. 05-5564) (National Institute of General Medical Sciences and Office of Science Education)
http://science.education.nih.gov/customers.nsf/MSInquiry.htm

TryScience
TryScience.org is your gateway to experience the excitement of contemporary science and technology through on and offline interactivity with science and technology centers worldwide. Science is exciting, and it's for everyone! That's why TryScience and over 400 science centers worldwide invite you to investigate, discover, and try science yourself.
http://www.tryscience.org

The Brain: Our Sense of Self (Grades 7-8) - Expand basic understanding of brain function and the nervous system. (National Institute of Neurological Disorders and Stroke and Office of Science Education)
http://science.education.nih.gov/customers.nsf/MSSelf?OpenForm

High School (Grades 9-12)

Mixing hot science with cool ideas.  This website for kids has over 100 different activities that can be done with materials all readily available at home.  Check out activities in chemistry, engineering, the five senses, forces and motion, life science, patterns, sound, structures, and water.
http://pbskids.org/zoom/activities/sci

Science NetLinks - Lesson plans and web resources of K-12 science teachers from the American Association for the Advancement of Science.
http://www.sciencenetlinks.com/index.php

Interactive Math And Science Websites
interactive websites for the math and science teacher. ... Middle & High School
Science.
http://www.slideshare.net/kbrooks/interactive-math-and-science-websites

High School Ace: Homework Help
High School Ace is a web directory of the best free educational resources for
high school students. It features academic subject guides, reference tools
http://highschoolace.com/

Exploratorium: Online Activities
Explore exihibitions, Webcasts, activities, and other Exploratorium online
resources. ... Exploratorium  The museum of science, art and human perception.
www.exploratorium.edu/explore/online.html