What happens to an ultrasound ray when it hits a boundary?

First off, Ultrasound is not a ray. Like all sound, its a wave. Ultrasound simply means its so low in pitch, its below the human hearing range.


When a sound wave hits a barrier, two things happen. The energy from the wave is partially absorbed into the barrier itself, which will now vibrate with that energy. Also, some of the energy from the wave is deflected, or bounced off.

Think of it as being how you can hear someone talk through a wall. Even though the sound waves are bouncing off the wall, and therefore a small room like a closet would amplify the sound, its still being transferred through the wall.