Wave packets  Wave packets. Use sliders to control group and
frequency components and check boxes to toggle visibility. For
the group component, the actual value is shaded but the outline
is also drawn over opposite side. When the group component value
is negative, multiplication by it reverses the sign of the
frequency component.  The wave packet is a proposed solution of
the wave-particle puzzle that was faced after discovering of
both Bohr atom quantization rules and electron diffraction. A
speed of the electron, computed from its mass and momentum, is
two times higher than the speed of the "electron wave", computed
from the estimated values of electric and magnetic fields
(mathematics is given at [1]). How can electron stay together
with its wave?  The problem  As the electron is also a particle
with at least approximate location and momentum, the wave
function of the moving electron must be nonzero over some
volume, but zero in the places the electron has not possibly
reached yet, and zero in the places