Hi, welcome to silkysteps :), open ended questions tend to begin with 'how, why, what if' and in contrast, closed questions might start with 'can, shall we, will, did, do, are'. The difference is between yes/no replies and inviting more open discussion or exploration.
If you have rice or other tactile medium in a tray what other resources are available?
Cups, pots, spoons, spades, tubes, funnels, sieves, pipes, buckets? These resources support action words/
verbs, descriptive mathmatical language - pour, fill, catch, sift, dig, full, empty, half, heavy, light, small, large, big, little and positional or directional language - in front of, behind, to th side, left, right, on top, above, below.
Extentions to tray filled media could be hiding items for children to uncover, unwrap, count, sort, order, share out. Adding other media to change a consistency, shape, quantity, colour, smell, sound. Encouraging transportation - taking the rice from one area to another.
Raw rice, puffed rice, cooked rice? with glitter, foil shreds?
adjectives or sensory words could be dry, soft, sticky, wet, shiny, reflective, crinkly, coloured.
Have tubes with lids to make shakers - see what wet rice sounds like in contrast to dry rice.
Focussed activity with small world figures invites role play - maybe for a conservation perspective
panda bears -
about on Wikipedia,
bamboo cane & leaves could be added to any rice exported by China.
Maybe play
lotto with a rice tray taking the place of a bag or the act of disguising the cards by turning them upside down on a table top? - artificial snow & snowflakes could be an interesting alternative for winter :) encourage team work and alter the rules a little, ask children to locate one single card hidden in the mixed media and then find a matching game board image for them to pair it up with - place on anyone's board as the turntaker's choice. First full card ends the game.
Sand and rice have similar attributes in the fineness of being dry, the clumpiness of being wet/damp, there is a different in grain sizes so will sift differently - rice puffs up when heated and can be eaten, sand melts at hot temperatures and makes glass. There's good reading in the
A practical guide to activities for young children on amazon.
I hope this helps xx