Universe Cycle - Geography (1)
Pre Lab 

   
OBJECTIVES:
  • Discovering a relief map.
  • Exploring different features on the Earth's surface.
VOCABULARY:
  • bay
  • geography
  • globe
  • map
  • mountain
  • peninsula
  • plain
  • relief
MATERIALS:

Students identify structures on a relief map.

BACKGROUND:

According to folklore, Christopher Columbus was practically the only person of his day who thought that the Earth was spherical in shape. Actually, the ancient Greeks Pythagoras and Aristotle both taught that the Earth was a sphere, and its diameter was calculated within 50 miles of the correct value by Erastothenes in about 220 BC. Educated people of Columbus' day were aware that the Earth was spherical.

The ancient Greeks used several lines of evidence to demonstrate the spherical shape of the Earth. They noted that the Earth's shadow on the Moon is curved during an eclipse, and ships going out of sight on the ocean disappear from the bottom up, as they move past the horizon. In 1522 the concept was proved to everyone when one of Magellan's ships returned to Europe, completing the first Western circumnavigation of the Earth. Today, pictures from spacecraft clearly demonstrate the spherical shape of the Earth. Students may be used to this concept, from watching media or video games.

We now know that the Earth is not a perfect sphere. Because of its rotation, the Earth actually flattens out at the poles, and bulges slightly at the equator. In reality, the Earth is thus slightly egg or pear shaped.

The Earth also differs from a perfect sphere in that its surface is irregular. These changes in elevation on the Earth’s surface, such as mountains, valleys, ocean basins, and plains, are called relief. Relief is intuitively understood by children because they see changes in the Earth’s surface whenever the go outside. In contrast, the spherical shape of the Earth is not apparent.

PROCEDURE:
  1. Explain the that the Earth is spherical in shape. You may wish to show them a globe, and pictures of the Earth from space. Ask the students if they can see the spherical shape of the Earth when they go outside. They should answer no. Discuss that early people thought that the Earth was flat, because it looked that way.

    Explain that it took many years for early scientists to determine the shape of the Earth. Go through the reasons of why we know it is spherical. Using the globe and toy boat, show the children why a boat might disappear from the bottom up. Tell them that they can see this if they watch a boat go over the horizon with a pair of binoculars.
      

  2. Explain that the Earth’s surface has relief. Introduce the following words to your students. Include any other words that may be appropriate for your region.

HILL - A large "bump" on the surface of the Earth, usually rounded on top. Use a local example that the children might know.

MOUNTAIN - A larger "bump" than a hill. A raised area is called a mountain if it is more than 2000 feet above its surroundings. A smaller "bump" is a hill.

VALLEY - A low, flat area between mountains or mountain ranges.

BAY - A protective, wide dent in the shore of an ocean or lake.

PENINSULA - Land that sticks out into the water, surrounded by water on 3 sides. 
 
PLAIN
- A flat area that extends over hundreds of miles. 

  1. Have the students explore the relief maps. Let them use their fingers to find examples of the vocabulary words listed above.

  [Dictionary]  
[Back to Universe Cycle Grid]
   [Back to Geography (1)]