Scattering due to magnesium oxide

My class were burning magnesium ribbon to make magnesium oxide. Then I turned on the projector. The light beam was clearly visible. The magnesium oxide smoke must have filled the room with tiny particles despite having the windows open. The smoke particles knock light sideways. This is called scattering. The picture shows the light coming sideways towards us despite giving the illusion of being the light that goes straight on.