Water reflects about 99.9 percent of airborne sound at its surface

Evidence

The impedance of water is about 3400 times larger than the impedance of air. You may have noticed that if you are underwater, it is very difficult to hear someone above water, even if he is shouting. Using formula 1.3 for the amount of energy reflected, we find that about 99.9% of the sound arriving from the air is reflected from the water surface. Sound launched within water travels quite well; if it reaches the surface, it reflects back down. — Eric J. Heller, Why You Hear What You Hear- An…, 98

Categorization

Category: Factual Claims

• SHARE: The 99.9% air-water reflection figure is a crisp, quantitative snippet for anyone interested in acoustics or underwater sound.
• XREF: Connects to why a whale breaching hears human voices so poorly—relevant to bioacoustics and the reader’s hearing question.

Related

• Nearly all sound energy is reflected at the air-water interface (similarity 0.94)
• Wind refraction and humidity structure alter sound propagation in air (similarity 0.79)
• Water damping is thousands of times stronger than air damping (similarity 0.78)

Broader Connections

• Directly exposing inner ear fluid to air would reflect 99.9% of sound energy #expands (0.95) — Eric J. Heller, Why You Hear What You Hear- An…, 1941