Even carbon dioxide can dissolve in the groundwater, causing the water to be naturally carbonated. This water is sometimes sold as mineral water. Groundwater can be heated by magma below the Earth's surface. The heated water can create hot springs, springs with water that is naturally hot (Figure 13.23). Some hot springs are used as natural hot tubs and are considered therapeutic and spiritual by some people. However, hot springs can be dangerous, too.
We used a level tablespoon of salt in a cup of water. The batteries we have shown here are more correctly called cells. An actual battery is made up of two or more cells. The zinc-air cell produces about three quarters of a volt.
Toxic Heavy Metals. Batteries are made from a number of different materials. These materials include acid, lead, nickel, lithium, cadmium, alkaline, mercury and nickel metal hydride.When batteries are not properly disposed of the casing can disintegrate and the toxic chemicals within can leach into the surrounding environment.n instances where the battery cannot be recycled, they are disposed of in a way that means the toxic chemicals cannot enter the environment. In some instances this involves encasing the batteries in concrete.