Here's a great craft to use some of those shells you or your kids pick up at the beach, courtesy of Disney FamilyFun magazine.
"This mini ocean made major waves with our kid testers, who loved to
send the shells, sand, and water tossing and tumbling. The project
starts with a clean plastic bottle (ours is an 18-ounce beverage
container). Pour in a cup of sand and add a handful of small shells (we
used 10). Mix a drop of green and a drop of blue food coloring into 6
cups of water, then use the tinted water to fill the bottle halfway. Add
a pinch of silver glitter. Fill the rest of the bottle with mineral or
baby oil, leaving as little air space at the top as possible. Run a line
of hot glue around the inside of the bottle cap, then quickly screw on
the cap to create a spill-proof seal."
