A log flume is a poplular ride in many theme parks. The idea is simple
- You and some friends sit in a hollowed-out log (or, more usually, a metal / fiberglass combination boat made to look like a log.
- The 'log' is lifted up (in much the same way as a rollercoaster might be) to a canal supported high in the air.
- The canal makes the log drift toward a big drop (usually on a strong, supported slope rather than a sheer waterfall-like drop)
- The log drops (or rather, slides) down toward a pool below.
- There is a large splash, getting the occupants wet.
This simple idea provides much entertainment. In almost every case I've seen, the splash-down happens in a place where the public (often those very individuals queuing for the ride) can witness it. In some circumstances, the resulting splash is so placed as to splash the observer. Thus is extra fun derived for nothing.