> obsessed with what floats and what sinks In an alternate timeline, there's an NSF science education wiki to point to, but oh well. You might seed the enviro

> obsessed with what floats and what sinks In an alternate timeline, there's an NSF science education wiki to point to, but oh well. You might seed the environment with cans of different sugar content https://www.youtube.com/watch?v=MzsORE0ae10&t=69 https://www.youtube.com/watch?v=MzsORE0ae10&t=69 , potentially helping with several common misconceptions ("heavy sinks", "metal sinks", "hollow floats"). Perhaps small plastic bottles with pennies. Pennies are also good for sinking boats. As a collaborative follow-up to the cans, perhaps a layered drink https://www.youtube.com/watch?v=sVsMmCb3Cdw https://www.youtube.com/watch?v=sVsMmCb3Cdw , or hand-mixed sugar water in those floating/sinking small plastic bottles. Other random fun density videos: Bubbles on CO2 https://www.youtube.com/watch?v=drBjDy96iNI&t=30 https://www.youtube.com/watch?v=drBjDy96iNI&t=30 and Al boats on SF6 gas https://www.youtube.com/watch?v=ckaJs_u2U_A https://www.youtube.com/watch?v=ckaJs_u2U_A . I've been exploring a "teach size down to atoms, then nucleons up to bulk materials", for early-primary. Thus the links.