From the article:
One of the most difficult to grasp aspects of quantum physics is how observing a quantum particle forces the particle's state to change.
This is known as the observer effect, and it is the result of the instruments necessary to measure the state of very small objects.
It's not the result of the instruments. It appears to be a result of the knowledge of the state of the photon. The classic double-slit experiment can be run with the photon detectors hooked up and running
but not recording the data and the interference patterns appear - but as soon as the data is recorded (or observed) the interference pattern disappears.
To really get into the spooky stuff check out the
Delayed Choice Quantum Eraser experiment where the interference pattern can be shown to manifest or not depending on a choice made by an instrument throwing out random choices
at a time after the photons should already either have taken an unknown path or a known path and hence produced the interference pattern or produced the two bright spots. Way cool!
Youtube has lots of videos on the delayed choice experiment.
If you're into this stuff, check out Tom Wheeler's video presentation where he describes using a piece of film that will be developed at a time
after the choice of whether or not to "know" the paths of the photons is made and guess what appears or doesn't appear on the developed film depending on what choice was made?
If you really want to get out there look into Jack Sarfatti's explanation of this effect (hint: retro-causal quantum interaction, ie. causing an action to happen or not happen in the past by a choice made in the present!)
Personally, this stuff is way too spooky for me. I like Einstein's opinion that "God doesn't play dice with the universe."
I find these things very interesting.
It would be great to be able to jump ahead 50 years and see what our knowledge of these things is then.