I have put together the following screaming information throughout 8 years of intense swimming pool research.
Screaming makes things more fun.
Going down a slide is alright, but going down a slide while screaming at the top of your lungs? Way more fun. This is especially fun with 150 people in the pool, every child has to outscream the surrounding children in order to prove that they are in fact having the most fun.
Every seventh scream is the loudest.
This works under the same principle as every seventh wave in the ocean being the biggest. There will be six or so mildly annoying screams and then it hits.
SCREEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEECH
And every adult in the pool winces while the lifeguards quickly check each other to make sure that is was in fact a child screaming and not a whistle blast signalling a major emergancy. This is lots of fun. In fact, often when there is a major emergancy no one comes to check for a couple minutes because it is assumed that a child was just screaming.
Two children screaming at just the right pitch can make the same noise as a Nazgul
Do you remember the eeeevil dark riders from Lord of the Rings? Do you remember thinking "What is that unearthly noise? What poor animal did they torture to make that sound?"
Yes, that was two screaming three year olds. I've heard that exact noise twice this week and I was amazed at how creepily evil it sounded.
Maybe the Nazgul also found that riding around killing people was way more fun if you scream a lot.