What is under an island?

We are studying islands! One big question that we have is: what is under an island? Before our research lab experimented today, some of us thought that islands were floating on top of the water. Some of us thought that islands are on top of piles of rocks. And some of us thought that islands were connected to the bottom of the ocean.

To find out if islands can be floating, we tried using common island materials: sand, rocks, and sticks. We worked in groups today to attempt to make these materials float. Only the sticks ended up floating, everything else sunk to the bottom of the containers. We concluded that the part of an island we can see above the water must be connected to a part below the water that touches the bottom of the ocean, lake, or river. Soon, we will learn about three different ways that islands can form. Look for future updates as our work continues!

We also thought about things that float, and put them on a continuum from small to medium to large. Things that float can be very large and very heavy!

Bonus science fact! The reason that sand and rocks sink is not because they are heavy. Many very large and heavy things can float. Giant cruise ships and oil tankers are a great example of this. Boat hulls can be made of very heavy materials like steel and concrete. Things float when they have positive buoyancy. A giant ship can float because even though it is very heavy, the volume of water displaced by its hull would weigh even more than it does!