Some cool ideas that came up for programs for younger kids:
Changing it up, taking the train
set away for the summer, replacing with scientist dress-up station, with lab coats, goggles,
beakers, lab supplies for creative play and exploration
Creating a hydroponic
garden or any kind of garden with kids for summer experimentation and overall deliciousness
Edible experiments in general (ideas can be found here and here)
Fossil
making (here's one method)
Borrow the Star Lab from your area CESA for a program
Labels: STEM, summer library program