A sensory bin is wonderful for preschool age children. Older kids might mess around a little in it, but it generally won’t hold their interest. My youngest loves the one at her preschool. They’re also very easy to make and switch up.
Find a good size bin to use. You want space for however many kids will use it, and sides high enough that it won’t spill too easily, yet low enough that the kids can easily reach into it.
Fill it with an inch or two of water, beans, rice, sand or anything else that will make a good base for the rest of the stuff in there. You will want to teach the kids not to eat or drink whatever you put in there.
Add in a variety of small, age appropriate toys. Make sure you consider what might get stuck inside the toys – small holes can fill quickly with rice or sand, for example, and that can be a pain later on.
Decide where you want to place the bin and let the kids go at it. Change the bin contents out regularly to keep things interesting. You can save sand, beans or rice for future turns back in the sensory bin so long as they look okay. Kids can gunk these things up over time, of course.