Here you go buddy boy:
Turbochargers and superchargers compress incoming air, causing it to become heated (see the universal gas equation). Since hot air is less dense than cooler air at the same pressure, the total charge delivered to the cylinders is higher than non-compressed air, but still less than it could be. By cooling the charge after compression, even more charge can be delivered, increasing power. Additionally, intercoolers help to increase the total amount of boost possible without causing engine knocking.