Current Events

  • Kansas Legislator Proposes Bill to Outlaw Sustainability Education
    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of ...Read more

    x

    Kansas Legislator Proposes Bill to Outlaw Sustainability Education

    A bill has been introduced in the Kansas legislature this week that would prohibit the promotion of sustainability. Here is a link to the one-page bill: http://www.kslegislature.org/li/b2013_14/measures/documents/hb2366_00_0000.pdf. See report on Bloomberg News.
  • Earth's Center Is 1,000 Degrees Hotter Than Previously Thought, Synchrotron X-Ray Experiment Shows
    Scientists have determined the temperature near the Earth’s center to be 6000 degrees Celsius, 1000 ...Read more

    x

    Earth's Center Is 1,000 Degrees Hotter Than Previously Thought, Synchrotron X-Ray Experiment Shows

    Scientists have determined the temperature near the Earth’s center to be 6000 degrees Celsius, 1000 degrees hotter than in a previous experiment run 20 years ago. These measurements confirm geophysical models that the temperature difference between the solid core and the mantle above, must be at least 1500 degrees to explain why the Earth has a magnetic field. For more information about this study, see the press release from the European Synchrotron Radiation Facility.
  • Ocean Volcanic Rocks Contain Samples of Recycled Crust
    Scientists have long believed that lava erupted from certain oceanic volcanoes contains materials fr...Read more

    x

    Ocean Volcanic Rocks Contain Samples of Recycled Crust

    Scientists have long believed that lava erupted from certain oceanic volcanoes contains materials from the early Earth’s crust. But decisive evidence for this phenomenon has proven elusive. New research from a team including Carnegie’s Erik Hauri demonstrates that oceanic volcanic rocks contain samples of recycled crust dating back to the Archean era 2.5 billion years ago. Their work is published in Nature. Oceanic crust sinks into the Earth’s mantle at so-called subduction zones, where two plates come together. Much of what happens to the crust during this journey is unknown. Model-dependent studies for how long subducted material can exist in the mantle are uncertain and evidence of very old crust returning to Earth’s surface via upwellings of magma has not been found until now. For more information about these results, see the press release from the Carnegie Institution.

"Build a Tree" Dendrochronology Activity

The interactive diagram below demonstrates a very simple model of tree ring growth.

Select a temperature range (Normal, Cool, or Warm) and a precipitation amount (Normal, Dry, or Wet) for the coming year. Click the "Add Yearly Growth" button. The tree (which you are viewing a cross-section of the trunk of) grows one year's worth, adding a new ring.

Add some rings while varying the temperature and precipitation. Which of these factors has a stronger influence on the growth of the type of tree being modeled here?

Use the "Reset" button to start over.

The "Show Specimen Tree" button displays a section of an "actual" tree specimen. Can you model the annual climate during each year of the specimen tree's life, matching your diagram with the specimen, to determine the climate history "written" in the rings of the specimen tree? (The "answer" is listed below, lower down on this page).

Some Limitations of this Tree Ring Model

Tree ring cross-section

Real tree rings are much messier than the ones in this simulation, but the same principles apply.
Credit: UCAR

"All models are wrong... some models are useful." - George E.P. Box

  • Real tree ring cross-sections are not so nice and perfectly circular (and centered), or even symmetric, like the ones in this model.
  • Different types of trees have different responses in their growth rates to temperature and precipitation. Some really like warm conditions, while others are happiest when it is especially wet.
  • Other variables (besides temperature and precipitation) influence growth rates of trees.
  • Real trees have a central section called the "pith"; our model starts right in with the first annual ring instead.

The annual climate sequence for the "specimen" tree in the interactive model, starting with the tree's first year of its 15-year long life, is:

  1. normal & normal (temperature & precipitation)
  2. warm & normal
  3. normal & normal
  4. warm & normal
  5. warm & dry
  6. warm & dry
  7. normal & dry
  8. normal & normal
  9. warm & normal
  10. normal & normal
  11. cool & wet
  12. normal & normal
  13. warm & normal
  14. warm & wet
  15. warm & wet

Please refer to our Changing Planet: Survival of Trees Classroom Activity and Video for more on tree rings.

Last modified October 15, 2011 by Jennifer Bergman.

Shop Windows to the Universe Science Store!

The Fall 2009 issue of The Earth Scientist, which includes articles on student research into building design for earthquakes and a classroom lab on the composition of the Earth’s ancient atmosphere, is available in our online store.

Windows to the Universe Community

News

Opportunities

Upcoming W2U Events
Join Today - Benefits,
No Ads!
Special Offers for Teachers
Member Benefits
Teacher Newsletter
Partnership Opportunities

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

World Leaders Developing a New Plan to Help Earth’s Changing Climate

Leaders from 192 nations of the world are trying to make an agreement about how to limit emissions of heat-trapping greenhouse gases, mitigate climate change, and adapt to changing environmental conditions....more

What Is Climate?

Climate in your place on the globe is called regional climate. It is the average weather pattern in a place over more than thirty years, including the variations in seasons. To describe the regional climate...more

Earth's Greenhouse Gases

Less than 1% of the gases in Earth's atmosphere are called greenhouse gases. Even though they are not very abundant, these greenhouse gases have a major effect. Carbon dioxide (CO2), water vapor (H2O),...more

Space Missions to study Earth's Atmosphere & Climate

Television weather forecasts in the space age routinely feature satellite views of cloud cover. Cameras and other instruments on spacecraft provide many types of valuable data about Earth's atmosphere...more

Modeling the Future of Climate Change

Predicting how our climate will change in the next century or beyond requires tools for assessing how planet responds to change. Global climate models, which are run on some of the world's fastest supercomputers,...more

Effects of Climate Change Today

The world's surface air temperature increased an average of 0.6° Celsius (1.1°F) during the last century according to the Intergovernmental Panel on Climate Change (IPCC). This may not sound like very...more

What Controls the Climate?

A factor that has an affect on climate is called a “forcing.” Some forcings, like volcanic eruptions and changes in the amount of solar energy, are natural. Others, like the addition of greenhouse gases...more

Shop Windows to the Universe

We now offer the Cool It! card game in our Science Store. Cool It! is the new card game from UCS that teaches kids about the choices we have when it comes to climate change.

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF