What does the gauge measure?

Whenever I'm idling, like at a local fast food restaurant, the needle goes down, and when I'm driving, its at the middle marker, but when I push the gas, it moves to just above that line. Is this normal, or am I just paranoid? I never noticed this before. I thought it always stayed around the middle marker.

Mine does that.

The reason the oil pressure changes is because at lower rpms the oil pump is not pumping as hard. At Higher RPMs it will increase. It is normal to see the guage fluctuate.

it is totaly normal to see the Oil Pressure Gauge flux like that. i think it even says it in the drivers manual.

ok, i just never noticed it before then, thanks :) i started paying more attention to my gauges ever since my car had overheated :)