Why are some beaches sandy?
Show answer & explanation
Answer: Waves grind rocks into sand
Waves grind rocks into sand ✓ — Correct! Sand is weathered rock broken down over millions of years. Rivers carry rock particles to the ocean. Waves continuously grind rocks, shells, and coral against each other, creating smaller particles. The constant tumbling action smooths and rounds grains. Quartz is common in sand because it's hard and resistant to weathering!
Fish waste creates sand — Wrong. Parrotfish do create some sand by eating coral and excreting it, but the vast majority comes from wave-eroded rocks and shells.
Volcanic ash settles there — Wrong. Volcanic beaches exist (black sand), but most sandy beaches form from wave erosion of rocks, shells, and coral over time.