Adding block ideas to Luanne’s list of domino alternatives above...
Wooden blocks are a better solution if you are doing this demonstration for a big group or in a sanctuary, and especially if you only have a carpeted floor.
Jenga blocks work well (even on low pile carpet, if that is your only alternative, as will non-Jenga brand stacking tower blocks like the kind you can sometimes find at a discount store.
Wooden play blocks also work on carpeted floors, and make a nice big noise in the Sanctuary when they fall --if you're using them in a children's sermon setting.
And look at these fun pirate stacking blocks I found on Amazon. They are dominoes in the shape of PEOPLE. - they come in other other "people" themes too. (Two tier tumbling stacking, anyone? Are we more stable when we hold each other up? Expanded teaching/story options with these.) Note that they are not as stable and will not work on carpet
