NASA's Climate Kids asks and answers important questions relating to climate change, such as "Do we care if Earth is getting warmer?," "What is the big deal with carbon?," and "What can we do to help?"
Start out with these big questions or pick one of the subtopics, such as "ocean" or "technology," to learn more about the impact climate change is having on one of these areas. Along the top, you can choose between the type of activity you're interested in—games, hands-on activities, and videos—and information you're seeking—career information and general knowledge.
Games range from find-a-word to sorting recycling from trash (and most require a Java-enabled browser and device). Hands-on activities are as diverse as building a terrarium, turning an old t-shirt into a bag, making s'mores using the power of the sun, and starting a science fair project. Careers you can learn about include a farmers market coordinator, a home energy auditor, and a green building contractor.
The big questions section of the site is a useful and accessible introduction to climate change and sections can be assigned as part of a lesson or in advance of it. It is particularly helpful in answering questions that continue to express doubt in human-caused climate change and the potential devastation that may arise as a result. You also may find this an interesting tool when promoting career resources in the sciences, particularly becuase there is not an emphasis on careers in a stereotypical lab setting.
Additionally, you will find classroom resources for grades 3–8 via the "teach" heading along the top ribbon. Included here are relevant standards, teachers' guides and toolkits from a variety of agencies and organizations, images, and PDFs. You may also find NASA's Global Climate Change site (helpfully linked in the header) a useful source of background information.
Going Green: An Earth Day Bibliography
K-12 | Teaching Aid
The Magic School Bus and the Climate Challenge
3-5 | Video
How We Know What We Know about Our Changing Climate
6-8 | Audio