need help with ADC readings

Hi all,
I would like to read the voltage from 10 different testing points, so I need to connect the pins with A0 to A9, however, I am only at very beginning step so I only connect one pin to A0, with the other pins unconnected, the reading from A0 is correct, but the reading from those unconnected pins does not show 0V, does anyone know what is wrong here? Maybe me could is incorrect. Could someone please provide me some testing code please?
Thanks in advance.


Floating analog pins read weird voltages on those pins. Connect something to them. I tested mine while troubleshooting another ADC challenge, and they convert to digital values 30 to 700 with nothing connected.

ok, I'll try it, thank you!

CMOS inputs are effectively insulated since the internals are all MOSFET devices where
the gate electrode is isolated with silicon dioxide layer. Silicon dioxide is basically glass...