Schrödinger's Cat seen within the box..

The wave function collapse locks the quantum state. The Observer Effect and Heisenburg's principle refer to the error of observation and that imparted by observation (unfortunately wave function collapse is also effected by an observer, but it isn't the "observer effect").

The wave function collapse therefore has an element of error caused by the observation such that our interpretation of the observation should be suspect as it might be in error...

That's my hair-splitting non-understanding and I stand ready to be run over by the bus of understanding...

Imagine you have a heavy bowl in the dark, on rails in front of you and you want to know its location. You don't have scales, but you do have those rails at least until the bowl. So you take a marble or perhaps a pool billard ball and roll it along the rails. You can determine the speed of your marble and when it reaches you after bouncing off the bowl you will have a time interval on your hands. You divide it in half and multiply it with your speed and voila - you now know where the bowl is.
Now imagine that it isn't a bowl anymore but a billard ball itself. You reckon if the rails aren't as smooth and clean behind it as they are in front of it, measuring its location with a cueball of your own would give you too big a margin of error. Well, it shall be the marble then. The marble is light so it won't thrust the billard ball too much. More, of course, than the bowling ball, but still good enough for your purposes. Eureka! you know how far that one was away, too.
Next you have a marble on the rails. A granite marble. You can't use your glass marble to measure that anymore, but you happen to have a light, wooden marble that you figure might just do the job. You have a big margin of error now. You know for a fact that the granite marble moved, not by millimeters anymore, but still way below meters.
And so you keep going deeper and deeper, to smaller and smaller particles. At some point all you can use anymore is a fine, fine spherical grain of quartz sand. Why didn't you use that all along, that ought to be much lighter than anything you measured! And it is, until what you measure is a grain of sand itself.

And this is when the observer effect kicks in. The location of the grain couldn't care less about you and what you know. But there is no way for you to measure it with something small enough and weak enough so that the measuring doesn't influence the phenomenon. There is only so small you can make your probe and beyond that you're left with uncertainty in your data. For all you know you could have broken the object you are measuring and it may no longer exist at all in the spot your returning grain reports. Maybe your grain doesn't return and you don't know if it past right by the target or if it was eliminated in the collision.

No, Mrs. McTaggart, it is not our knowledge of things that determines them. It is our measuring sticks. We can't make infinitely perfect measuring sticks, not so much because of the limits of our knowledge or technology, but because there is only so low you can dig the ground before you hit bedrock; only so sharp you can grind the blade until you've sanded it all the way through.

Thank you, Arkayik. I knew they were different, and I knew the "Observer Effect" was about the margin of error, but I didn't know if there was a singular term to explain what "locks" the state, and I was afraid I'd made that all up to sound smart. It's nice to know I was almost right.

Don't be too hasty to judge you wrong or me right in this regard. We are discussing Quantum Physics....

Just hangin my ignorance out there waiting for the thwack on the noggin.... :pinch: