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Structure of Earth

Key Stage 3

Meaning

The structure of Earth is what the Earth is made from, underneath the surface.

About the Structure of the Earth

EarthStructure.png
A diagram showing the layers of the Earth.

Key Stage 4

Meaning

The structure of Earth is what the Earth is made from, underneath the surface.

About the Structure of the Earth

The structure of Earth has been discovered by observing seismic waves.
Both P-waves and S-waves are refracted as they move through the Earth which gives information about the density underneath the surface of Earth.
S-waves do not travel through liquids, as they are absorbed, so this can show where there is liquid underneath the surface of Earth.
SeismicWaveEarthStructure.png
This diagram shows the path of seismic waves through the Earth.

P-waves are refracted gradually as they pass deeper into the Earth because the rock becomes more dense the deeper down.

P-waves are refracted at the interface between the Mantle and the Outer Core. This causes some P-waves to change direction and results in a 'shadow zone' between 100° and 145°, from their source, where P-waves do not reach seismic detectors.

S-waves do not pass through liquids and are not detected beyond 100° from their source. This shows that the core of the Earth must be a liquid.

References

Edexcel

Structure of the Earth, page 37, GCSE Physics; The Revision Guide, CGP, Edexcel