I have two variants of this. The 'things from nature' basket which just has shells, wood, stones, feathers etc and 'natural objects' basket including many items from here. This was an easy place to start.
Looking for a fun activity that kids busy for hours? This DIY Silly Putty recipe takes less than 5 minutes to make and kids LOVE squeezing, pulling, stretching, and playing with their very own putty! Plus it only requires 2 common household