Why does the Arduino have so many Analog Input pins?

From my experience with my arduino, I have found that it cannot accurately measure voltage inputs from two pins at the same time; one input seems to effect the value of the other. What other uses are there/am I missing something, can the arduino record data from multiple analog inputs simultaneously?

They all share the same sample and hold circuit, so with high-impedance inputs, the previous reading(s) will effect a reading.

If you're doing something where this is a problem, take a couple of readings and discard the first few.

From the learning section we see that it takes 100 micro seconds to read an analog input, try just using a delay. Hopefully 0.1 milliseconds is close enough to simultaneously for you...

tonyu22:
I have found that it cannot accurately measure voltage inputs from two pins at the same time;

I assume by "at the same time" you mean "consecutively".

tonyu22:
one input seems to effect the value of the other. What other uses are there/am I missing something, can the arduino record data from multiple analog inputs simultaneously?

What you are missing is that your voltage source output impedance is too high. From the datasheet: "The ADC is optimized for analog signals with an output impedance of approximately 10 k