Fourth Grade
Worksheets
Studying Ocean Floor Sediments
How do scientists know what the Earth was like long ago? One way is to study fossils of plants and animals that lived long ago. These fossils can be large - like dinosaur fossils - or they can be small. Ships take core samples from the ocean floor. Much of the sediment that makes up the ocean floor is the remains of tiny marine animals. When the animals died, their shells settled to the bottom of the ocean.
The ocean floor may have sediments that have accumulated there for a million years. To take core samples, ships send down a hollow steel tube to the ocean floor. It makes a hole into the sea floor. Then a sample of the sediment is pulled into the hollow tube. It is brought into the ship to be studied.
