Suppose you want a glass of 50 degree C water, but all you have is a hot tap and a cold tap that produce typical streams of water at 98 and 2 degree C respectively. So you fill the glass halfway with 98 degree water, stop that tap, then move over to the cold tap. When the stream of cold water hits the hot water, some drops splash out, like when your poop hits the toilet water and water splashes back out.

1. Why does this happen??
2. What is the average temperature you'd expect the water that splashes out to be?

I'm sure the problem is underspecified; feel free to make whatever reasonable assumptions you think are necessary.

Thanks very much in advance.