This is a first for us, unsure we didn't think of this before but my kids love playing with both so why not add them together?!Ice and rice are both great sensory play objects and can be used many different ways. In this bin we made coffee ice and made the rice green with food coloring.
Other ideas are
~adding some objects to the liquid before you freeze it
~making the rice different colors
~adding different toys (my little pony is big in this house right now that is why we used them, but use your kids favorite toys)
~let your kids use their sense in this play time. (how does everything smell?, how does the ice and rice feel?,what color are the ice and rice?, and if your okay with it let them even lick the ice to see how it taste? again you use juice to make the rice or even flavored water. I just wanted to use coffee so I could make them a "mountain")