Classroom Activities for the Geologic Time Scale

The history of the planet is divided into time periods, called the geologic time scale by geologists, scientists who study the earth. From Paleozoic to Cenozoic, and the eons in between, the periods are based on rock sequences and are measured by years. Learning the relationships and differences of these periods, and the long-lasting historical impact of the periods, leads to investigative activities in the earth science classroom.

The Beginning

The clouds appeared 3 billion years ago.

Tape 46 sheets of white paper along the top of a whiteboard. Hang the papers so that they are not overlapping and there are no gaps. Explain to the students that Earth is 4.6 billion years old. Each of the white papers represents 100 million years of Earth's history. Starting with the paper that is the farthest to the left, write on the paper, "4.6 billion years ago," on the next paper write, "4.5 billion years ago," and continue until the last paper says, ".1 billion years ago." Give each pair of students a different milestone of Earth to research to place on the time line you have just made. Milestones that are important to the time line include formation of the moon, appearance of plants, clouds formed, oceans formed, land animals appeared and humanoids appeared. Place these important events on the time line by their proper dates.

How the Rocks Line Up

Layers of rocks are full of Earth's history.

Divide students into groups of three. Each group excavates a 5cm layer of the trash can. Scientists study layers of rocks to understand the history of Earth. The students study layers of trash to learn what they can about the history of the classroom. Students sketch the items they pull out of the trash can. The class discovers the oldest trash is deposited at the bottom of the can, similar to how the oldest rock layer is deposited with layers on top of it. The trash can is a changing record of the history of the classroom, just like the rock layers are a changing history of the Earth.

Age of the Dinosaurs

Dinosaurs were part of the Mesozoic Era.

Assign the groups of three a dinosaur from the Mesozoic Era to research. The students find the diet, habitat, scientists' explanation for extinction and physical appearance. Give the students time in class to do the research on the Internet. The students draw the dinosaur to a scale of 1 inch equals 1 foot on a piece of butcher paper. If their dinosaur is 10 feet tall, they would draw it 10 inches tall. Cut out the dinosaurs and place them on a bulletin board in your classroom. The students work on making the proper habitat for the dinosaur by creating the proper foliage out of colored butcher paper, according to the dinosaur's diet.

Earth's Layers

Draw and label the three layers of the Earth on the whiteboard: the core, the mantle and the crust. Explain to students that the crust is made up of tectonic plates, about 20 huge slabs of rock. These plates are moving and scraping against each other, causing earthquakes. Give each student a boiled egg, a plastic knife and a paper plate. They will use the egg as a model of the Earth. Instruct the students to tap the egg lightly. The cracked shell will represent the crust. Show the students how to manipulate the moving and scraping of the eggshell to represent the crust. Use the knife to cut the egg in half vertically. The white part of the egg is a model of the mantle. The yolk represents the core. The students draw on white art paper a cross-section of the Earth with the three parts labeled.