A terrarium is a miniature garden enclosed in a transparent container, often made of glass or plastic. It creates a self-sustaining ecosystem where plants can thrive with minimal maintenance. Terrariums can be open or closed, depending on the humidity and plant types used. They are popular for indoor decoration and can house various plants, such as ferns, mosses, and succulents. Creating a terrarium involves layering materials like gravel, activated charcoal, and potting soil to ensure proper drainage and aeration. This small ecosystem relies on the water cycle, where moisture evaporates and condenses, providing hydration to the plants. Terrariums are often used in educational settings to teach about ecosystems and plant care.