Can someone help me understand what they mean when they say our observation changes the state of matter? I've watched videos on quantum entangelment and the light through slits test and I still don't know what they mean when they say observing it changes the outcome??? What does me watching or not watching have to do with the way reality plays out?

You need first to understand the word observing in this context means 'interacting'.

 

Any interaction with the outside world, animate or inanimate is classed as an observation.

That thing which you use to observe something will determine how you see it and even 'what' something is. seeing photons as particles or waves depending on the method. You cannot look at something without interfering with it, in some way.

Edited October 8, 201510 yr by StringJunky

Can someone help me understand what they mean when they say our observation changes the state of matter?

Act of observation, either direct (by eye) or indirect (by camera), is stealing photons from environment.

That's, photons which would normally bounce back and forth, are absorbed by eye, or by sensor in device, and are no longer part of system under observation.

 

"Observation"/"measurement" in context of double slit experiment, often means usage of polarization filter.

 

Act of measurement in electronics, electricity, is also changing state of circuit.

If you plug Ampere meter serial in circuit it has as small as possible resistance, to not influence measured current flowing through wire.

If you plug Voltage meter parallel in circuit it has as large as possible resistance, to not influence measured voltage.

Either "as small as possible" is not 0, nor "as large as possible" is not infinite.

If they would be 0 and infinite, there would be no influence (and in fact we wouldn't be able to measure), but they are not.

Edited October 9, 201510 yr by Sensei

Ok that makes sense. Thanks guys!