Book 6, Question 94
Why Is a Lagoon Calmer than the Open Sea?
A lagoon sits behind a reef or an island. The reef works like a breakwater, a wall that takes the punch of big ocean waves. So outside the reef the waves smash, and inside the lagoon the water stays calm.
From the book
Page from A Million Whys Book 6
More fun facts
- Coastal lagoons are shallow and separated from the ocean by an island, a reef or a sand bank.
- Lagoons connect to the sea only through narrow inlets.
- At Laguna de Terminos in Mexico, a barrier island 2.5 kilometers wide slows the flow between the lagoon and the sea.
- That lagoon has two inlets. Seawater usually flows in at one end and out at the other.
- In the Arctic, scientists use satellites to track when lagoons freeze, break up and open to the ocean.
Sources: NOAA Ocean Service, NASA Science, National Park Service
Questions kids ask
What keeps a lagoon separate from the ocean?
An island, a reef or a sand bank, with only narrow openings to the sea.