Flashback 4 Billion Years

Go back in time to explore how Earth formed and how the first oceans came to be. You’ll learn about Protoearth, a hot, early version of our planet, and the processes that helped shape it into the world we know today. Through a creative comic strip activity, you’ll visualize key steps like cooling, outgassing, condensation, and early ocean formation. This lesson helps connect Earth’s history to the oceans that support life today.

Introduction: 

Learning about the ocean is important to understanding much of what happens today in our climate and on our planet in general. Part of this is learning about how the planet and our oceans were first formed. Let’s dive in! 

Earth is the third of eight major planets in our solar system that revolve around the Sun. The Sun and our solar system formed around 5 billion years ago from a huge cloud of gas and space dust called a nebula. At this point, the planets were protoplanets, Earth was “Protoearth”. There’s a prefix there, ‘proto’. Can you think of other words with ‘proto’ — maybe prototype? ‘Proto’ means first, original, or early. So, Protoearth was an early or first version of Earth. 

In this activity, we’re flashing back over 4 billion years to Protoearth to understand how the planet and our oceans were first formed. It is hard to imagine 4 billion years ago when the Earth was nothing like it is today and our solar system was young. But, by making a comic strip, we are going to learn about this fascinating process.

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Materials:

• Workbook page or blank paper divided into 6 sections
• Colored pencils or crayons

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Procedure:

1. Getting Ready: It's time to make a comic strip! For each box on your paper, draw a picture to the corresponding event in the formation of our ocean. Use your imagination! If you would like, you can include labels or arrows too. Ready? Let's go!
2. Create Your Comic: As we move through each stage, draw a picture in each section of your comic strip.
   1. We’re going back in time, 4 billion years ago, rewind past human civilization, past early humans, past the time of dinosaurs, past the beginning of life, to the formation of Earth. At this time, 4 billion years ago, our planet was much different from today. The temperature was so hot that all of the rocks were molten, meaning they were liquid. This early version of our planet, was called PROTOEARTH, and it was just a small, soft ball of molten rock with no oceans at all.
   2. Over millions of years, little by little, PROTOEARTH began to cool off a little and a hard outer crust was formed. There were cracks and crevices in this new crust and water vapor and other gases from inside the hot interior were released through the cracks. This is called OUTGASSING. These gases enveloped PROTOEARTH and formed an early atmosphere. At this point, the temperature of the Earth’s crust was 600 degrees celsius.
   3. Eventually, the planet cooled and condensation occurred. What is condensation? Have you ever held a cold bottle of water on a hot day? The bottle starts out dry but pretty soon, it is wet with water droplets on it. Has this happened to you? You might wonder where the water came from... Well, there is water vapor in the air and when the warm air touches the cold bottle, it cools down and the water vapor turns into a liquid. This is the process of condensation and it happened to PROTOEARTH. Eventually, the Earth cooled to a temperature below the boiling point of water and the water vapor in the atmosphere that was released during outgassing condensed and fell to the earth as rain! All this rain collected in low lying areas and formed big pools.
   4. At this time, there was so much activity in space with new planets being formed and stars colliding and exploding that comets, asteroids, and meteorites were really common! These big hunks of ice and rock would fall to Earth and bring more water that helped to fill the early oceans.
   5. During this time, there was nearly non-stop rainfall. Some scientists think it could have rained for millions of years! All this rain fell on Earth’s rocky surface and dissolved the rocks. The elements and compounds from the rocks that were dissolved by the rain were carried to the newly forming oceans and are what made the oceans salty!
   6. Eventually, space activity slowed down, the Earth stopped being bombarded by cosmic collisions and the oceans were able to stabilize and reach a chemical balance. This is how the Earth’s oceans were first formed!