Batteries provide portable, convenient sources of power without wires. It makes many mobile devices possible! The common type of battery is called the dry cell battery. There are three parts of a battery: the anode, the cathode, and the electrolyte. The anode (- side) and cathode (+ side) are two conductive materials. The electrolyte is a chemicals that does not allow electrons to pass through it. Due to a chemical reaction, a large quantity of electrons builds up in the anode. The electrons want to flow to the cathode, but the electrolyte prevents that. When the battery is party of a circuit and the circuit is closed, the electrons flow from the anode, to through the wire, powering the load, and goes back into the anode. The chemical reactions alters the anode and cathode and that is why a battery “dies”. Without batteries, many modern devices would not have been possible!