Energy can be stored in a capacitor by separating charges and placing them on opposite plates. The amount of energy stored depends on the charge on the plates and the capacitance. When a dielectric material is placed between the plates, it becomes polarized by the electric field, increasing the capacitance. The dielectric constant is a property that determines how much the capacitance increases. The electric field strength inside the dielectric is reduced compared to without it, allowing higher voltages to be achieved before dielectric breakdown occurs.