What heats the earth's core?

The temperature of the center of the Earth is estimated to be higher than ___________.

About how fast does the mantle "flow"?

What contributes up to 90% of the Earth's interior heat?

• Latent heat from the core's expansion

• Heat left over from Earth's formation

• Radioactive decay of isotopes

• Gravitational heat from differentiation

What is the mantle primarily made of?

• Solid rock

• Viscous molten rock

• Ice

• Liquid metal

What is the size of the Earth's inner core compared to?

• The size of the sun

• The size of a football field

• The size of Mars

• The size of the moon

True or False: Small amounts of radioactivity happen in Earth's crust.

• True

• False