Energy in the Geosphere

Learning Goals:1. Understand that there are 3 plate boundaries

and that specific geological events occur at each boundary.

2. Understand that the movement of plates occurs as a result of energy in the core of the Earth. (Nuclear: Radioactive Decay)

3. Understand that changes in density result from temperature inputs.

4. Understand that changes in density create convection currents.

A little Review• Basic Definitions

– Mass: • the amount of matter in an object

– Volume:• the amount of space an object occupies

– Density:• the ratio between the mass of the object and the amount

of space that the object occupies

• The FormulaDensity=mass/volume

Density Calculations

• Example #1– Calculate the density of a 23g rock with a volume

of 3.2cm3.

D=m/vD=23/3.2D=7.19g/cm3

Density Calculations

• Example #2– The solid inner core of the Earth has a density of

approximately 13g/cm3. Calculate the mass of 5cm3 of this substance.

D=m/v13=m/513*5=m65g=m

Understand that there are 3 plate boundaries and that specific geological events occur at each boundary.

• Transforming Boundary– Definition:

• Two plates sliding next to each other in opposite directions.– Geologic Feature

• Strike-Slip Fault Line

• Diverging Boundary– Definition:

• Two plates moving away from each other.– Geologic Feature

• Oceanic Ridge/Location where “new” surface rock appears

• Converging Boundary– Definition:

• Two plates sliding toward each other.– Geologic Feature

• Oceanic Trench/Mountain Building/Volcanic Activity

Understand that the movement of plates occurs as a result of energy in the core of the Earth. (Nuclear: Radioactive Decay)

The Composition of the Earth

Understand that the movement of plates occurs as a result of energy in the core of the Earth. (Nuclear: Radioactive Decay)

• The Inner Core: Solid Iron; b/c as radioactive elements decay they keep releasing energy until they become stable.

• The Outer Core: Liquid Iron; b/c as radioactive elements decay they release energy (Thermal)

• Lower Mantle: Liquid; convection currents• Upper Mantle: (Asthenosphere) Solid-ish; as the distance

from the core increases, materials begin to solidify.• Crust (Lithosphere) Solid; this is where the plates are

located

Understand that changes in density result from energy inputs.

An increase in temperature is an energy input or energy transfer!

• As temperature ↑, volume ↑;• As temperature ↑, mass↔;• As temperature ↑, density ↓.• As the density of an object ↓,

the object will go ↑.

Understand that changes in density create convection currents.

Material near the core is heated by radioactive decay.

The heated material becomes less dense and rises.

The material moves away from the heat source and cools.

The cooled material becomes more dense and falls.