The earth is an oblate spheroid - a sphere with flattened poles and a slight bulge at the equator.

    The earth's polar diameter is 12,640 km, while its equatorial diameter is 12,683 km. Its equational circumference is 39.842.72 km.

    As the earth rotates, its side that is lighted by the sun is day time, while its side that is in darkness is night time.

    The earth rotates in counterclockwise direction or from west to east. Hence, we see the sun rise in the east.

    The earth rotates at the speed of 1,680 km per hour or 28 km per minute.

    The axis of the earth is tilted 23.5 degrees. Because of this tilt, the hours of day and night are not exactly 12.

    A revolution is the journey of the earth around the sun. The imaginary path followed by the earth is its orbit.

    It takes the earth 365 1/4 days to make one revolution. The period of time it takes a planet to complete one revolution is called a year.

    The earth is revolving at a speed of 105,600 km per hour or 1,760 km per minute.

    The orbit of the earth is elliptical. The point in the orbit nearest the sun is called perihelion, while the point farthest is called aphelion. The average distance of the earth from the sun is 148,800,00 km.

    Seasons occur because the tilt of the earth's axis. In the Northern Hemisphere, the summer has longer days and shorter nights. During winter, there are shorter days and longer nights. The opposite occurs in the Southern Hemisphere.

    The globe is a model of the earth. The top of the globe is North, its bottom is South, its left side is West, and its right side is East.

    The lines drawn from the North Pole to the South Pole are called meridians. The line drawn from the West to East are called parallels.

    The distances measured in degrees north or south of equator are called latitude. Longitude is the distance measured in degrees east or west of the prime meridian.

    The prime meridian is at 0 degrees longitude, and the international date line is at 180 degrees. The equator is at 0 degrees latitude.

    To find the exact location of a place at the globe, find its latitude and longitude.

    A map is a flat or graphic representation of the earth's surface. The art of map making is called cartography.

    To read a map, take note of the compass direction, the legend, and the reference lines.

    The 24 time zones on the earth correspond to the 24 meridians drawn on the globe at 15 degrees intervals.

    The calendar shows the 12 months of the year. September, April, June, and November have 30 days, and the other months have 31 days, except February, which has 28 days.

    地球是一个扁平的球体--一个具有扁平的两极和赤道附近稍稍凸出的球体。

    地球的极直径是 12,640 公里，而它的赤道直径是 12,683 公里。它的平均周长是 39,842.72 公里。

    因为地球自转，它被太阳照亮的一侧是是白天，而处在黑暗中的一侧是夜晚。

    地球按照逆时针方向或者由西向东自转。因此，我们看到太阳从东方升起。

    地球以每小时 1,680 公里或者每分钟 28 公里的速度自转。

    地球的轴线倾斜 23.5 度。因为这个倾斜，白天和夜晚的小时数并不全是 12.

    公转是地球围绕着太阳转的旅程。地球所遵循的假想路径是它的轨道。

    地球花 365又1/4 天完成一次公转。这个一颗行星完成一次公转所花的时间被称为一年。

    地球以每小时 105,600 公里或者每分钟 1,760 公里的速度公转。

    地球的轨道是椭圆形的。在轨道上最接近太阳的点被称为近日点，而最远离太阳的点被称为远日点。地球离太阳的平均距离为 148,800,00 公里。

    因为地球轴线的倾斜而发生四季。在北半球，夏季具有较长的白天和较短的夜晚。在冬季则是昼短夜长。相反的情况发生在南半球。

    一个球体可作为地球的模型。球体的顶部是北方，它的底部是南方，它的左侧是西方，而它的右侧是东方。

    从北极到南极划出的线被称为经线。从西向东划出的线被称为纬线。

    赤道以北或者以南以度数测量的距离被称为纬度。经度是本初子午线以东或者以西以度数测量的距离。

    本初子午线处于 0 度经度，而国际日期变更线处于 180 度经度。赤道处于 0 度纬度。

    为了在这个球体上找到准确的位置，要找出它的纬度和经度。

    地图是地球表面的平面表示或者图形表示。地图制作的技术被称为地图学。

    为了读懂地图，要注意指南针方向、图例以及基准线。

    地球上的 24 个时区与在这个球体上按 15 度的间隔画出的 24 根经线相对应。

    日历显示一年的 12 个月份。9月、4月、6月、11月有 30 天，而其它的几个月除了2月份 28 天之外，都有 31 天，.