Try the experiment in your bathroom. Turn on the tap until you get a thin, steady flow of water. Comb your hair and place the comb near the point where the water emerges from the tap.
Large deflections can occur.
The molecules of water are electrically neutral but, like the molecules of other dielectric substances, they are characterised by regions of positive and negative charge. Because water is not a metal, the charges are not free to migrate through the dielectric substance in the direction of the field. The charges on each molecule therefore neutralise each other, except at the water-air interface that is closest to the comb, and also at the interface farthest from it. In these regions, they are not paired with opposite charges, so they build up areas of equal positive and negative charge on the opposing sides of the cylindrical water surface. The stream is now polarised, and it is this property of polarisation that allows dielectric materials to be attracted to a source of electrical field.