Mrs. Degl1 It appears that Earth is a perfect circle, however, it is not!!!!! It is really an OBLATE SPHEROID. What does that mean?????????

Mrs. Degl2 Let’s review first: Circumference is the distance around the outside of a sphere. Diameter is the distance from one side, through the center, to the other side. Radius is the distance from the outside into the center. In other words, it is half of the diameter.

Mrs. Degl3 The diameter through the Equator is larger than…….. the diameter through the poles. The Earth is the same shape as an egg…Oval… Oblate Spheroid. This shape is exaggerated.

Mrs. Degl4 The truth is that the earth is really 99 percent round, so it appears to be a perfect circle. Your weight is different on the Equator than it is on top of either of the Poles. Do you weigh more on the Equator or on the poles? Why?

Mrs. Degl5 How did people like Christopher Columbus know that the Earth was not flat? There are 5 basic proofs that the Earth is not flat and is actually curved: 1.How ships disappear from the bottom up as they move away into the horizon. 2.During a Lunar Eclipse, a curved shadow of the Earth is cast on the Moon. 3.Noticeable differences in gravity measurements (weight) from the Equator to the Poles. 4.The changing altitude of Polaris (North Star). 5.Actual photographs from satellites in space. On the last page of this packet, we will be drawing diagrams describing each proof.

Mrs. Degl6 Latitude Longitude Latitude and Longitude is the coordinate system used to locate positions of the Earth.

Mrs. Degl7 Facts about Latitude : 1.The lines go from left to right (side to side). Latitude lines are called parallels. 2.The numbers are located on the right and left of a map. 3.Even though the numbers are on the right and left of a map, latitude measures the distance North or South of the Equator. 4.Latitude goes from 0 º to 90 º North and South of the Equator. 5.All of the United States is North of the Equator. 6.The Equator is 0 º latitude 7.The Poles are 90 º latitude. One is 90 º North and the other is 90 º South.

Mrs. Degl8 Facts about Longitude: 1.The lines go from top to bottom. Longitude lines are called meridians. 2.The numbers are located on the top and bottom of a map. 3.Even though the numbers are on the top and bottom, longitude measures the distance East or West of the Prime Meridian. 4.All of the United States is west of the Prime Meridian. 5.The Prime Meridian is 0 º longitude. 6.The International Date Line is 180 º longitude. 7.Longitude goes from 0 º to 180 º The Earth rotates 15 º of longitude EVERY HOUR, from West to East (left to right).

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10 1 º = 60 ‘ One degree equals 60 minutes ¼ º = 15 ‘ One quarter of a degree equals 15 minutes ½ º = 30 ‘ Half of a degree equals 30 minutes ¾ º = 45 ‘ Three quarters of a degree equals 45 minutes Latitude and Longitude are broken down into smaller units. These units are called minutes and seconds, but have NOTHING to do with time. On the next slide we will learn how this works.

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