Book 6, Question 5
Why Does the Shore Keep Changing?
Waves, tides, storms, and rivers all move sand. A beach is a pile in motion. Today's beach is last year's sand, just passing through!
From the book
Page from A Million Whys Book 6
More fun facts
- Waves usually hit a beach at an angle but wash straight back, so they slowly move sand and gravel along the shore.
- In one person's lifetime, a shoreline can grow or shrink by more than 10 feet.
- Waves, wind, storms and floods all reshape shorelines.
- Even calm seas keep moving water, sand and mud toward and away from the shore.
- Shorelines move forward and back over times as short as seconds and as long as thousands of years.
- Changes in sea level also control where a shoreline sits.
Sources: National Geographic, National Park Service, WHOI, UH
Questions kids ask
Can a beach grow?
Yes. Over a lifetime, a shoreline can grow or shrink by more than 10 feet.