The EPA has tons lessons and activities about air, climate change, ecosystems, energy, health, water, and reduce, reuse, recycle. I've already found 6 that match what my students are learning about next week! I also found that the EPA offers grants to groups/school districts for environmental education. Wish I'd known that before the deadline.
human blood lesson plan - love the model of the blood
Science with Kids: Salt Volcano. A salt volcano acts a lot like a lava lamp- kids are in awe over this fun Science
Lesson plans + extension activities for every Magic School Bus show.
Science for Kids: Overnight Crystal Garden - Babble Dabble Do (uses epsom salts)
40 STEM (science, tech, engineering, math) apps for kids.