A water molecule, a commonly-used example of polarity. The two charges are present with a negative charge in the middle (red shade), and a positive charge at the ends (blue shade).
well its because the electrons of the atoms of hydrogen are strongly attracted to the oxygen atom and are in reality closer to the core of the oxygen than their own cores. This is why water has a negative charge at its center (red color) and a positive charge at its ends (blue tint).This is a consequence of the high electronegativity of the oxygen atom. Electronegativity being its capacity to ”attract” electrons due to his configuration. Yes its configuration because if you look for oxygen in a periodic table you’ll see that it has only 2 shells and it has 8 protons in its nucleus so his capacity to ”drag” electrons is high since his atomic radius is relatively short (with only 2 shells that are ”pulled” to the center by his 8 protons). So logically, since an atom hydrogen has only 1 proton in its nucleus its obvious that its electrons will be ”attracted” to the oxygen’s nucleus.