Electrodes are conductive materials that allow electric current to enter or leave a medium, such as a solution or a gas. They are commonly made from metals like copper or platinum and are essential in various devices, including batteries and electrochemical cells. When a voltage is applied, electrodes facilitate chemical reactions, enabling the flow of electricity. In everyday life, you can find electrodes in items like smartphones and medical devices. For instance, in a heart monitor, electrodes attach to the skin to detect electrical signals from the heart. This information helps doctors monitor heart health and diagnose conditions effectively.