I can hear the ocean!

Isabella and Ayla discovered that they could hear the ocean in the shells.  They shared their discovery at our reflection time and we had a very interesting discussion on how that could be.  The children thought:

• there might be water in there 
• it's because there is sand in there
• it is because they are from the ocean

See if you can find out why we can hear a sound like the ocean in a shell we hold to our ear.