What kind of surfaces will reflect sound waves effectively?

Hard, flat surfaces are highly effective at reflecting sound waves due to their physical properties. When sound waves encounter a hard, flat surface, they bounce off these surfaces with minimal absorption, allowing the sound to travel further and maintain its intensity. This is similar to how a basketball bounces off a gym floor; the energy is efficiently transferred back into the environment, rather than being absorbed or dissipated.

In contrast, other materials like carpets, curtains, and soft plush fabrics are designed to absorb sound, reducing the reflection of sound waves. These materials convert sound energy into a small amount of heat and minimize echoes, which is why they are commonly used in environments where sound control is desired. Absorbent fabrics serve a similar purpose, as they are engineered to diminish sound reflections rather than enhance them. Hence, hard, flat surfaces stand out as the best option for effective sound reflection.