Two kids in black trunks bouncing on a wet trampoline.
Children play on trampolines outdoors.
Kids are children, bouncing on a trampoline is the same as playing on a trampoline and it makes sense for a trampoline to be outdoors.
The children consist of two kids.
The word children indicates there is more than one kid, so two kids qualifies as children. They are bouncing on a wet trampoline. The trampoline would probably not be wet unless it was outside and exposed to rain or dew. Bouncing on a trampoline is playing, so the children play on the trampolines.