For our first science playgroup, I thought I would start with something low mess and that was magnetic play.
Discount School Supply has a couple of great sets of large magnetic wands, metal balls and little metal colored tabs. Add in an office supply magnet set, tin cans and various weird items with magnets glued to them and it was a big opportunity for open play.
Some children built towers, testing the limits of magnetism. Others turned the tin cans into funny faces. It was fun seeing how they continued to extend the play.
It was easy to clean up, for our first time families, it wasn’t too intense. A good introduction to the fun that can be had with science.