Water is the only common substance that when you freeze it, it's volume INCREASES.
When the pipe originally held the "all full" volume and the the water expanded, it put a tremendous amount of pressure on the pipe. Enough pressure and the pipe would burst.
Gamma rays are not magnetic
The array will be created with the elements equal to null.
The method is called the displacement method.
You place some water in the graduated cylinder and measure its volume.
Then you add your object and measure the new volume.
The difference between the two volumes is the volume of your object.
