Batteries have been around longer than many people tend to think. In 1938, archaeologist Wilhelm Konig discovered some unusual clay pots while excavating in a town just outside what is now Baghdad, Iraq. The vessels, which measured about 5 inches long, included an iron rod encased in copper and dated to 200 B.C. Investigations suggested that the vessels had once been complete with an acidic substance such as vinegar or wine, leading Konig to think that these vases were ancient batteries. Since this discovery, scientists have created imitation pots capable of producing an electric charge. In 1799, Italian physicist Alessandro Volta made the first battery by stacking alternating layers of zinc, cloth, and silver. This procedure, called a voltaic pile, was not the first device to generate electricity, but it was the first to release a constant current. However, there were some flaws in Volta's creation. The vertex at which the layers could be arranged was restricted because the mass of the stack would have squeezed the brine out of the fabric. Metal discs also tended to crumble quickly, shortening battery life. Despite these shortcomings, the SI unit of electromotive force is now called the volt in honor of Volta's achievements. The next breakthrough in battery technology came in 1836 when English chemist John Frederick Daniell designed the Daniell cell. In this initial battery, a copper plate was placed in the bottom of a glass jar, and a copper sulfate solution was cascaded over the plate to fill the jar halfway. Then, the zinc plate was wrapped in the jar and a zinc sulfate solution was added. The zinc solution drifted to the top of the copper solution and bounded the zinc plate because the copper… in the center of the paper… y. However, LiOn batteries are not currently available in standard sizes such as AAA, AA, C or D, and are significantly more expensive than their older equivalents. Charging can be tricky with NiCd and NiMH batteries, because people have to be careful not to do it. overload them, as this may lead to reduced capacity. To prevent this from happening, some chargers simply turn off once charging is complete. NiCd and NiMH batteries also need to be serviced, meaning a person should fully discharge them and recharge them occasionally to reduce any loss of capacity. LiOn batteries, on the other hand, come with refined chargers that prevent overcharging and never need to be tuned. Even rechargeable batteries wear out over time, although it may take hundreds of recharges before this happens. When they finally run out, be sure to dispose of them at a recycling center.