Observer effect (physics)

<p>In <a href="/facts/Physics/a7aH2y08">physics</a>, the observer effect is the disturbance of an observed system by the act of observation. This is often the result of utilising instruments that, by necessity, alter the state of what they measure in some manner. A common example is checking the pressure in an automobile tire, which causes some of the air to escape, thereby changing the amount of pressure one observes. Similarly, seeing non-luminous objects requires light hitting the object to cause it to reflect that light. While the effects of observation are often negligible, the object still experiences a change (leading to the <a href="/facts/Schr%25C3%25B6dinger%2527s_cat/UpNp6vVu">Schrödinger's cat</a> thought experiment). This effect can be found in many domains of physics, but can usually be reduced to insignificance by using different instruments or observation techniques.
</p><p>A notable example of the observer effect occurs in <a href="/facts/Quantum_mechanics/BRc3Mzgr">quantum mechanics</a>, as demonstrated by the <a href="/facts/Double-slit_experiment/TR8zwEcy">double-slit experiment</a>. Physicists have found that observation of quantum phenomena by a detector or an instrument can change the measured results of this experiment. Despite the "observer effect" in the double-slit experiment being caused by the presence of an electronic detector, the experiment's results have been interpreted by some to suggest that a conscious mind can directly affect reality. However, the need for the "observer" to be conscious is not supported by scientific research, and has been pointed out as a misconception rooted in a poor understanding of the quantum wave function ψ and the quantum measurement process.
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Observer effect (physics) open-in-new

Observer effect (physics)