Water is a really good conductor of sound so I would have to say that it would be to send the message underwater because a more dense medium produces a louder sound
Bohr, he invented the Bohr model which is the basis for the beginning of quantum physics.
(C) Air Resistance
<u>Explanation:</u>
When an object falls through air, air resistance acts on it in upward direction. When air resistance acts, acceleration during a fall will be less than g because air resistance affects the motion of the falling objects by slowing it down. Air resistance depends on two important factors - the speed of the object and its surface area. Increasing the surface area of an object decreases its speed.
I'd say diffraction since sound waves can bend around objects like corners. Let's say you're in the hallway and you can hear sound coming from a door. The sound waves diffract around the door and spread out into the hallway, making it possible for you to hear.
Also, you can hear it before you see it because light waves are shorter than sound waves and hardly diffract around doors.
