Teacher's Guide: Where Did the Oxygen Go?

Links to Standards

Concepts covered in this week's story that relate to State and National standards include:

&bull Earth changes over time.

&bull Animals depend on plants for oxygen.

&bull Materials cycle through different parts of Earth, including the atmosphere, lithosphere, and biosphere.

Background

This week's news story comes from the following articles, reported in the August 30, 2007 issue of the Journal Nature :

Kump, L.R. & Barley, M.E. Increased subaerial volcanism and the rise of atmospheric oxygen 2.5 billion years ago. Nature 448(7157), 1033

Lyons, T.W. Paleoclimate: Oxygen's rise reduced. Nature 448(7157), 1005

Curriculum Connections

This week's story can easily be linked to Mathematics, Arts, and Language Arts curricula. Large numbers like millions and billions can be difficult for students to comprehend. Give students everyday examples of the relationship between 1, 1 million, and 1 billion. For example, count out one second. Tell students that 1 million seconds is equal to about 12 days. One billion seconds is equal to about 32 years. You may wish to read, "How Much is a Million" by David M. Schwartz. Even older students can benefit from the visual representations of large numbers and discussion about the examples in the text.

Answer Key

1. Use context clues in the second paragraph to write your own definition of the word photosynthesis.

Photosynthesis is the way that plants make sugars/food using sunlight, water, and carbon dioxide.

2. How are gases from underwater volcanoes different than gases from volcanoes on land?

Gases from underwater volcanoes react more quickly with oxygen than gases from volcanoes on land.

3a. Write out 2.7 billion and 2.5 billion using numbers.

2,700,000,000 and 2,500,000,000

3b. Subtract 2.5 billion from 2.7 billion. Show your work.

2,700,000,000

- 2,500,000,000

= 200,000,000