Model
Anything that represents the properties of an object.
Gravity
An inward pulling force. This force pulls inward equally in all directions and cause the earth to become spherical.
Circumference
The enclosing boundary of a curved geometric figure.
Oblate Spheroid
A sphere that bulges slightly at the poles. The shape of the earth.
Gradient
An increase or decrease in the magnitude of a property.
Elevation
Height above a given level.
Contour line
A line on a map joining parts of equal height above or below sea level.
Latitude
Angular distance of a place north or south of the equator.
Longitude
Lines east and west of the meridian.
International Date Line
The line that separates the days. one earlier than another.
Time Zone
The time in which you live in. Based on Greenwich, England.