Ionization smoke detectors are devices that detect smoke and fire by using a small amount of radioactive material. This material ionizes the air in a sensing chamber, allowing a small electric current to flow. When smoke enters the chamber, it disrupts this current, triggering the alarm. These detectors are particularly sensitive to fast-burning fires, such as those caused by paper or flammable liquids. However, they may not be as effective for smoldering fires, which produce more smoke before bursting into flames. Regular maintenance and testing are essential to ensure their proper functioning.