Lets face it capacity is fun, but messy, so it's a great chance to get outdoors and the keep the cleaners your friends!
This year I use rice and lentils to teach my class about capacity. We filled our builders tray (tuff spot) with the lentils and collected up different types of containers. What holds the same amount? How many scoops will fill the cup?
Using lentils and rice was a more sensory experience for the children and they didn't get soaking wet!