What is an upside down river?
The Yarra River in Melbourne is an upside down river. The dirt is on the top
Do you mean can you tell when your about to go upside down or that you can feel it when your already upside down? Because to the first, if your observant or have ridden the ride before, and the second, yes, you can tell when your upside down. > Your body would be able to feel the centre of gravity changing.
I will do an experiment with myself tonight. My PURPOSE is to learn if people can actually sleep upside down. REASON: I want to figure out if people can really sleep upside down. hypothesis: I bet people can sleep upside down peacefully. experiment: I will sleep upside down tonight and come back tomorrow and type what happened.