Proof the earth is ROUND

Fresh water:

1%

Ice:

2%

Oceans:

97%

Gravity:

A force of attraction

Photos of the earth from space

Best way of knowing the shape of the earth

Inner earth

Determined by studying earthquakes

Mantle

Hard rock

Sextant:

Instrument that measures the altitude of polaris

Gravity depends on....

Mass and distance

Outer core

Melted iron (liquid)

Asthenosphere

Melted rock

The height polaris changes as you go....

North or south

Polaris

North star

Ships appear to disappear as they sail away because...

Sailing around the curved surface of the earth

Inner core

Solid iron

Crust: lithosphere

The crust and the upper mantle that form an outer shell around the earth

Atmosphere

The layer of gas that surrounds the earth

Hydrosphere

The layer of liquid water that rests on the crust

The altitude of polaris is....

Your altitude