Origins: Back to the Beginning
To learn about the elements and their roles in the universe.
- copy of the "Elemental Puzzler" student handout
All the elements known are formed in stars. This activity will help
students explore some of the elements found in the Periodic Table of Elements
and what role some of them play in the universe.
Ask students how many elements they think exist in the Periodic Table (as of
mid-2004,there were 115 elements; elements 116 and 118 were believed to have
been found but scientists later retracted results).
Review the table's basic organization (see Activity Answer for more
You may want to note to students that the table is subject to change; new
elements are added as they are discovered (only 94 of the elements exist
naturally on Earth). Most of the heavier elements, which are created in
particle accelerators or nuclear accelerators, exist for a fraction of a second
Have students do the puzzle. If they are having difficulty, point them to
the following Web sites:
WebElementsTM Periodic table
Periodic Table of the Elements
Elements in Fireworks
When students have completed the puzzle, tell them that some of the elements
listed in their puzzles have a special significance to the universe. Have
students research answers to the questions on their handouts that are related
to what role some of the elements play in the cosmos. Review student answers as
a class, clarifying any misconceptions students may have.
As an extension, have students research the astronomer's periodic table of
elements that maps the abundance of the elements in the universe. Ask them to
choose one of the elements on the table and create a poster about its role in
the universe. Find one table at www.webelements.com/webelements/elements/text/periodic-table/geol.html
Investigate what elements make up in the sun and learn about cosmic
microwave background radiation in this American Museum of Natural History site
that offers articles and student materials related to NOVA's "Back to the
Dmitri Ivanovitch Mendeleev published the first iteration of the Periodic
Table of Elements in 1869. The modern table is divided into metal, nonmetal,
and metalloid groups. Each group contains elements with similar physical
properties. Metals make up 75 percent of the table.
In each horizontal row, the number of protons increases from left to right,
starting with hydrogen, which has one proton. The number of protons in an
element defines its atomic number. Elements along each row have the same number
of principal electron shells (energy levels) while in an unexcited state, while
elements found in vertical columns have similar outer electron configurations.
Elements in the first two and last six columns have the same number of outer
shell (valence) electrons (transition elements in the ten intervening columns
follow a separate set of rules).
The five most abundant elements that make up atomic matter in the universe and
the approximate percentages in which they occur (as a percentage of total
number of atoms)are hydrogen (91.2%), helium (8.7%), oxygen (.078%), carbon
(.043%), and nitrogen (.0088%). Approximate percentages by mass are (71.0%),
helium (27.1%), oxygen (.97%), carbon (.40%), and nitrogen (.096%).
Some facts about hydrogen's role in the universe include that it is the most
abundant element in the universe, it is the starting point for thermonuclear
fusion, and it forms the molecular hydrogen clouds where stars are born.
Nitrogen and hydrogen combine to make ammonia. Iron is the final element
created before a star undergoes a supernova explosion.
NOVA Web Site—Origins
In this companion Web site to the program, find out how life could have
started and why water is needed for life; read about the latest discoveries in
origins research; use raw data to assemble the famous Eagle Nebula image;
insert your own values into the Drake Equation; decode cosmic spectra; and
The Electromagnetic Spectrum
Provides an activity that allows students to identify substances based on the
visible spectra they emit.
Timeline of the Universe
Offers a tutorial that traces the 15-billion year history of the universe,
including the big bang, element formation, planetary system formation, the
creation of Earth-like planets, and the chemistry of life.
Universe Forum: Learning Resources
Includes FAQs about the cosmos, information about the Center for Astrophysics'
online telescope network, and links to additional lesson plans and
WMAP Related Educational Resources
Provides an overview of the project, classroom exercises, commonly asked
questions about the universe, a glossary, and more.
Couper, Heather and Nigel Henbest.
Big Bang: The Story of the Universe.
New York: DK Publishing, Inc., 1997.
Follows the story of the universe from its birth to the present and beyond.
Waves: The Electromagnetic Universe.
Washington, D.C.: National Geographic Society,1996.
Simplifies and clarifies the electromagnetic spectrum with colorful images and
A Guide to the Elements.
New York: Oxford University Press,1996.
Serves as an introductory resource, beginning with the basic concepts of
chemistry and tracing the history and development of the periodic table of the
elements. Each element is presented individually and accompanied by a
photograph and practical application.
The "Mission: The Search for Life" activity aligns with the following
National Science Education Standards:
Science Standard B:
Properties and changes of properties in matter:
Science Standard B:
Structure and properties of matter:
Classroom Activity Author
Developed by WGBH Educational Outreach staff.