I always thought there was something wrong with my cars coolant temp. Its never at the same spot meaning sometimes the gauge reads at the lower part of the normal operating level and other times somewhat in the middle. Today I got off the highway after a 25 mile trip @ 80mph. My temp. gauge was a little below the middle mark and I took a sharp left turn through an intersection and my temp instantly shot down to where the normal operating level begins. Then it slowly came up again. WTF? Is this normal? It always seems to be fluctuating but never overheats. (knock on wood)

I need advise. Could it be a trapped air bubble?

Thanks.