Basic circuit question concerning ground

in the book "getting started with arduino", figure 4-6, page 43
the pushbutton was connected to pin 7, the pushbutton was also connected to ground on the same side. i was wondering, how come the pin (pin 7) can't be connected the the other side of the pushbutton ( the one that's not connected to 5V) when i tried connecting it to the non-grounded (5V side), it wouldnt work. can someone please explain this to me? I'm new to electronics and arduino. thanks

Use a meter and buzz out the push button, see what is connected to what when not pressed, and when it is pressed.

CrossRoads:
Use a meter and buzz out the push button, see what is connected to what when not pressed, and when it is pressed.

Which means use a digital multi-meter set to continuity test mode (often also doubles as diode test mode - may be marked with a diode symbol), which goes "beep" when you touch the probes together. Use that to see which pins on the button are linked together when it's either pressed or not pressed.