In 1800, Alessandro Volta discovered the battery. William Nicholson and Anthony Carlisle, while investigating how electricity moved through this new device, found the exact proportion of gas it takes to make water. Humphry Davy replicated the experiment and discovered a new chemical element, potassium. He did not understand why metals changed or appeared when electricity is run between two metals within a liquid conductor. A few years later, Michael Faraday realized that some metals did not conduct electricity. He found that an electrical current modified the device's materials. He named this discovery electrolysis, and created a new vocabulary including anode, cathode, and electrolyte.