Applications: Real-world uses of a scientific principle or technology. Table of Contents Ultrasound Noise Cancellation The Diffraction Horn Harmonic Synthesis In this section we will be exploring applications of sound. We will talk about ultrasound and how it is used in sonar and echolocation, diffraction horns, and noise cancellation. Along the way, you may become interested in a particular application and want to know about the physics behind it. If so, just click on the physics image at the bottom of the page. So, what's sound really good for? Click on the forward arrow to find out . . .