Canal & Water Tower SystemCreate your own canal systems at different heights and watch the water flow. This canal system is also great to use with marbles, golf balls or table tennis balls. The canal system is ideal to use in the sandpit but it can also be used on grass, dirt, wood chips or even in the classroom, just don't get water on the carpet. This Tower system allows the children to build their own unique designs to study the cause and effect of their design on the speed