Rocks and Fossils for Kids: Igneous, Sedimentary and Metamorphic (Grade 4 Science)

Hi, I'm Luna from DoodleBeez. Today we are rock detectives. We will learn the three kinds of rock, how they form, and how fossils tell us stories about life long, long ago.

The first kind is igneous rock. Deep underground, rock melts into a hot liquid called magma. When magma or lava cools and hardens, it becomes igneous rock, like granite or basalt.

The second kind is sedimentary rock. Wind and water carry bits of sand, mud and shells. They settle in layers. Over a very long time, the layers are pressed and cemented into rock, like sandstone.

The third kind is metamorphic rock. Metamorphic means changed. When rock is squeezed and heated deep inside Earth, without melting, it turns into new rock. Limestone can become marble.

Fossils are the remains or traces of living things from long ago. An animal dies and is buried in mud. Over thousands and thousands of years, minerals replace its bones or shell, and it turns to stone.

Fossils are clues. In rock layers, the deepest layers are usually the oldest. And if we find fossil sea shells high on a mountain, we know that land was once under the sea.

Now it's your turn. A rock has layers, and inside it is a fossil fish. Which kind of rock is it? Pause and try. It is sedimentary rock, because fossils form in layers of sediment.

Great job! Remember, igneous rock forms from cooled magma, sedimentary rock forms in layers, and metamorphic rock is changed by heat and pressure. Fossils are clues to the past. Practice rocks and fossils in the Science Lab at doodlebeez.com. See you next time!