"BrainPop" www.brainpop.com An engaging site for all subject areas. Thanks Alexandra for the recommendation!
"Project Learning Tree" https://www.plt.org/activities-for-families/ Outdoor hands-on learning activities around observation.
"Scholastic Weekly Reading and Science Activities" https://classroommagazines.scholastic.com/support/learnathome/grades-3-5.html
https://sites.google.com/berkeley.net/3-5resourcesforhomelearning/projects University of Berkeley online and hands-on activities.