Science Grades 3-5
CSI Activities - Some activities needed a little scaffolding, but they were wonderful at giving students a glimpse of what real detective do, even the not-so-fun stuff like staying within budget when running tests. You could honestly do a whole unit from the site alone, and students would love it!
Fuddlebrook - If you have the budget, this is an engaging resource that covers science and ELA standards in a fun way. Join Mrs. Wigglebum's class as you read through stories and complete inquiry-based, hands-on activities.
Mystery Science: the Case of the Missing Bicycle (Grades 3-4) or Mystery Science: The Case of the Missing Lunch; you can do one or both of these before doing the CSI Activities listed above, if you want to have a longer unit.
Civil Air Patrol Aerospace Education - For only $35, you become a member for life! This means you have access to all their curriculum, books, STEM materials and kits for the rest of your teaching career. My only complaint is that the site is very poorly organized and difficult to navigate. However, they are more than happy to help via email and respond quickly. Absolutely worthwhile.
Slideshow for their 3rd/4th grade curriculum to help you get started! (You'll need a membership to see the content of these lessons, but this organized all of them for you, adds videos, and more!)