Properties refer to the characteristics or attributes of a material or substance, such as its color, density, hardness, and conductivity. These properties help in identifying and classifying materials, allowing scientists and engineers to understand how they will behave under different conditions. For example, the thermal conductivity of a material determines how well it can conduct heat, which is crucial in applications like insulation. Applications are the practical uses of materials and their properties in various fields. For instance, metals are often used in construction due to their strength and durability, while polymers are utilized in packaging for their lightweight and flexible nature. Understanding properties enables the development of innovative solutions in industries like electronics, medicine, and automotive.