Scattering can polarize light. Place a polarizing filter between the Mini Maglite and the first hot-glue stick. Rotate the filter while one person views the glue stick from the top and another views it from the side. Notice that when the top person sees a bright beam, the side person will see a dim beam, and vice versa.
You can also hold the polarizing filter between your eye and the glue sticks and rotate the filter to make the beam look bright or dim. The filter polarizes the light and so does the scattering. When the two polarizations are aligned, the beam will be bright; when they are at right angles, the beam will be dim.
Scattering polarizes light because light is a transverse wave. The direction of the transverse oscillation of the electric field is called the direction of polarization of light.
The Mini Maglite's beam contains photons of light that are polarized in all directions: horizontally, vertically, and all angles in between. Consider only the vertically polarized light passing through the glue sticks. This light can scatter to the side and remain vertically polarized, but it cannot scatter upwards! To retain the characteristic of a transverse wave after scattering, only the vertically polarized light can be scattered sideways, and only the horizontally polarized light can be scattered upward (click on the diagram below to enlarge).