How can a waterplay activity be varied with ability?
Preschool age? It might help to know about the activity or equipment you have. Some little ones have better coordination than others, so there could be different items to pour water into which are wider (easier) or narrower (more difficult). You can do activities around which items will sink or float. Have the kids try to predict whether it will sink or float, then try it (a toy boat or duck will likely be one of the easiest for them to tell you, a more unusual object would be more difficult) There could be some kind of imaginative play that ranges from simple to more complex, e.g. a tea party with water for tea, pretending to be in a car wash, bathing dolls, etc. You could have a bubble making activity. The kids who are more able could try to make bigger bubbles, join bubbles together, etc. You could do color mixing in water.