A
quantum-mechanical principle with the consequence that
the position and momentum of an object cannot be precisely determined. The
Heisenberg principle helps determine the size of electron
clouds, and hence the size of atoms.

A
consequence from quantum
mechanics: the position and the momentum of a particle can not be determined
with the same accuracy at the same time. When for example the speed of an electron is well known, it's position is
unpredictable within a certain volume. This effect is negligible in
macroscopic dimensions.

A
quantum-mechanical principle with the consequence that
the position and momentum of an object cannot be precisely determined. The
Heisenberg principle helps determine the size of electron
clouds, and hence the size of atoms.
[NTN] "The more precisely the POSITION is determined, the less precisely
the MOMENTUM is known" [Werner Heisenberg]

A
quantum-mechanical principle with the consequence that
the position and momentum of an object cannot be precisely determined. The
Heisenberg principle helps determine the size of electron
clouds, and hence the size of atoms.
[NTN] "The more precisely the POSITION is determined, the less precisely
the MOMENTUM is known" [Werner Heisenberg]