Did this in grade science fair! DIY Amazing Density Tower from Things Found in Your Kitchen by stevespanglerscience: Make objects float in the middle of a liquid with this amazing trick.
Cause & Effect STEM in hands-on engineering play with tangible materials for Rube Goldberg Machines (via TinkerLab)
Disney Cast Member service pins & name tags - what the special pins mean **Although Pluto is used on the five year pin now
Awesome hands-on science activity -- fun way to be a detective at home! Includes a great book list of fun mystery reads too.
Use this (awesome) list of apps to help kids stay sharp on problem-solving, creativity, & critical thinking by learning how to Code! Great for Brownies Computer Expert Badge for Junior Entertainment Badge