Heuristic Play is the term that Elinor Goldschmeid used when describing how a toddler interacts with objects. It is about providing open-ended learning opportunities for young children and this can be achieved by creating Treasure Baskets that have items of 50-60 natural or found objects (that are small but not too small) from around the house or garden and simply sit back and let them freely explore using all of their senses!
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.