Geology: History of Earth

Geology: History of Earth
Lou Hoover: Education, Arts, Letters and Ideas

Skill: High School/College
Time Required: One Week


In 1894, Lou Hoover entered Stanford University where she became the first woman to major in geology.  At a dinner hosted by her professor, Lou met Herbert Hoover, a fellow geology major and discovered that they both had much in common, including being geology majors and a love of fishing.  During geology field experiences, Lou and Herbert fell in love.  Lou and Herbert became international travelers and one day while in England she discovered a rare geology book, Agricola de re Metallica, which was written in Latin.  Together the Hoovers translated the Latin text into English.  Their efforts resulted in a gold medal from the Mining and Metallurgical Society of America.


In this lesson, students will gain an understanding of the history of the earth as well as understanding of the study of geology.

Materials Required:

Access to the internet and/or access to a public library; flour, salt, cardboard or plywood and tempra paint


Assign each pair of students one of the following time periods:
  • Holocene
  • Jurassic
  • Mesozoic
  • Miocene
  • Oligocene
  • Ordovician
  • Paleozoic
  • Paleocene
  • Precambrian
  • Permian
  • Phanerozoic
  • Pleistocene
  • Pliocene
  • Proterozoic
  • Quaternary
  • Silurian
  • Tertiary
  • Tommotian
  • Triassic

Each pair of students is responsible for researching the time period assigned and answering the following question:
  1. During that particular time period, was the earth different or the same as it is now with regard to the continent, seas and ocean formations?
  2. What caused these differences?
In addition to finding the answer to these questions, have each pair of students create a salt and flour map of the earth as it was during their time period. Have them use the Web Geological Time Machine as a reference for how their maps should look.  The following are directions for making salt and flour maps: 
  1. Outline a map on heavy cardboard or plywood
  2. Each student must mix 2 cups flour, 1 cup salt and ¾ cup water adding a little water at a time. 
  3. Add more flour if needed
  4. Spread the dough over the outline of the map
  5. Shape mountains, valleys, etc.
  6. Wet fingers to smooth rough spots
  7. Allow to dry
  8. Paint with tempra paint
  9. Create color key for map
A note of caution: Do not do this project on a rainy or very humid day because the humidity with make the map run. 

Extending the Lesson:

To extend this lesson tell students to imagine that a time machine exists and that they can travel through time.  Have students write a creative short story of travel from now to the time period they researched.

Sources & Resources:

Web Geological Time Machine
Recipes for Salt Maps
Images of Salt Maps
    Fortey, Richard.  Earth: An Intimate History.  New York: Vintage, 2005.

   Gohau, Gabriel, Carozzi, Albert V. and Carozzzi, Marqueritye.   A History of Geology.  Piscataway: The State University of Rutgers, 1990.

   Hartmann, William K. The History of Earth: An Illustrated Chronicle of an Evolving Planet.  New York: Workman Publishing, 1991.

   MacDougall, J. D.  A Short History of Planet Earth: Mountains, Mammals, Fire, and Ice.  Hoboken: John Wiley & Sons, Inc., 1996.
Credits: This lesson was written by Debra L. Clark, Kent State University