Understanding the layers inside Earth is a bit tricky because we can’t just dig down to study them. Scientists have to use different tools and methods to learn about the Earth's crust, mantle, and core.

One important method is called seismology. This involves studying seismic waves, which are waves made during earthquakes. As these waves move through the Earth, they change speed and behavior based on what type of material they go through. For example, these waves move faster in solid materials than in liquids. This difference in speed helps scientists figure out that the inner core is solid, while the outer core is liquid.

Scientists also use other tools, like gravity and magnetic measurements. By looking at how gravity changes, they can learn about the density of different layers inside Earth. This tells them more about the complicated structure beneath our feet. Studying Earth’s magnetic field helps scientists understand what is happening in the outer core, where liquid iron is moving around and creating the magnetic field we see.

Doing experiments in the lab is really important too. Scientists can recreate the very high temperatures and pressures found deep inside Earth. This helps them study how different materials behave under these extreme conditions, such as how certain minerals change form deep within the Earth.

Finally, scientists look at materials that come from volcanoes and pieces of mantle rock brought to the surface by magma. These pieces give them direct samples of what the mantle is made of and provide real evidence of the conditions that exist many kilometers below the surface.

By using these different methods together, scientists can create a clearer picture of what Earth’s insides look like. This helps them make new discoveries about the history and processes of our planet.