If it is a copper or metal pipe, tap the pipe gentle with a some thing metal (screw driver/small wrench ect...) If the pipe makes a echo sound it is empty, if the pipe has water in it, It will not echo. this also works with pro pain bottles and other metal objects
By looking at the check or globe valve
Highly sensitive listening gear while water flows through the pipe
You would have to taste the water running through, the more salty it is.. most likely its made from a valley LOL
Hydro electric energy is extremely safe, all that happens is that water streams through a pipe which moves a tubine inside the pipe which is connected to a generator which generates electricity that is sent straight into the power grid. its simple
Your windows fog up horribly and sometimes you can hear what sounds like water running through your dash when your driving.
U tell me
You can tell if the roof vent pipe is clogged by watching for slow drains. If air is unable to help force water out of the system, the water will naturally want to remain in position.
3 diff. signs. check the Anti-freeze/coolent tank and see if theres oil in it, or check the oil and see if theres water in it. Or a big black cloud shoots out the tail pipe when it is running,
The position of the handle indicates the direction of the opening through the ball, IE. handle in line with pipe, valve is open, tangent to pipe, valve is closed.
witch pipe and will tell u :)
Below the frost line of your area. Your local building code will tell you what the requirements are.
water in oil The smell of anti-freeze at the tail pipe (sweet, sickly smell)