Uncertain Observer

Heisenberg and Schrödinger get pulled over for speeding.
The cop asks Heisenberg "Do you know how fast you were going?"
Heisenberg replies, "No, but we know exactly where we are!"
The officer looks at him confused and says "you were going 108 miles per hour!"
Heisenberg throws his arms up and cries, "Great! Now we're lost!"
The officer looks over the car and asks Schrödinger if the two men have anything in the trunk.
"A cat," Schrödinger replies.
The cop opens the trunk and yells "Hey! This cat is dead."
Schrödinger angrily replies, "Well he is now."

[Explaination: Schrödinger's cat is a thought experiment, sometimes described as a paradox, devised by Austrian physicist Erwin Schrödinger in 1935. It illustrates what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects. The scenario presents a cat that may be both alive and dead, this state being tied to an earlier random event. Although the original "experiment" was imaginary, similar principles have been researched and used in practical applications. The thought experiment is also often featured in theoretical discussions of the interpretations of quantum mechanics. In the course of developing this experiment, Schrödinger coined the term Verschränkung (entanglement).

In quantum mechanics, the uncertainty principle is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle known as complementary variables