Snowball Earth

High school (ages 12+)
Environment & Earth

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/snowball-earth

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. How big is Snowball Earth?Near-complete glaciation of Earth's surface, including oceans
2. What is the geological epoch?Cryogenian Period (approximately 720–635 million years ago)
3. What is the key geological evidence?Diamictites and dropstones found at tropical paleolatitudes; banded iron formations
4. What was the Snowball Earth hypothesis?It says that long ago, Earth may have been almost completely covered in ice, from the poles to the equator, during the Cryogenian period about 720 to 635 million years ago.
5. How do scientists know Earth might have been a snowball?They find glacial deposits called tillites and dropstones in rocks that were once near the equator, plus banded iron formations that show a frozen ocean.

Geohistorical Hypothesis: A scientific idea about Earth's past geological events and processes.
Albedo: The measure of how much light that hits a surface is reflected without being absorbed.
Paleolatitude: The latitude of a location in the geological past.
Silicate Weathering: The breakdown of silicate rocks by chemical reactions with water and air.