A battery is made by connecting a metal that tends to lose electrons with another metal that tends to gain electrons. Two metals that make for a good battery are copper and zinc, both of which are found in any post-1982 penny. Zinc has a low melting point, which makes it easy to remove from the inside of the penny. Get a ceramic bowl and then, wearing safety glasses, grab a post-1982 penny with metal tongs or pliers and place that penny over a blue flame, such as from a Bunsen burner or a kitchen gas stove. After a minute or so, the penny will appear to blister. At this point quickly bring the penny over the ceramic bowl. Tap the tongs or pliers on the bowl’s edge to cause the molten zinc to drip into the bowl. After it cools, clean it off in running water. Touch the smooth side of the zinc to the very tip of your tongue alongside a new clean penny. As the two metals make contact on the wet surface of your tongue, you will be able to sense a small tingling, warming sensation. That’s the electric current running between the two metals. Notice this happens only when the zinc and penny are together. You have made a battery out of a penny! Why is the effect more pronounced when your tongue is wet with salt water?