Keystone species puzzle

What is a keystone?

You might think that all arches are made the same way. The fact is they are not all the same.

It is true that Egyptian, Babylonian, Greek and Assyrian civilizations used arches for underground structures such as drains and vaults. However, it was the Roman civilization (1000 B.C.E. - 500 C.E.) that first began using a keystone (also called a capstone) in their arches. The keystone is the topmost stone in the arch. The one in the illustration on the right is exaggerated in size from what a normal keystone would be. The keystone helped to distribute the weight down the side supporting blocks (voussoir blocks) of the columns. With this design, the keystone is the "key" to supporting the arch, because if you remove the stone, the arch would collapse.

arch with keystone animation Test and see what happens when you remove a keystone from the arch above by placing your mouse point on the arch.

How can you build the sides before inserting the keystone?

During construction, a temporary wooden frame supported the side voussoir blocks until the keystone was inserted. After the keystone is inserted, the wooden frame is removed.

 

 

 

 

View Citation

You may need to edit author's name to meet the style formats, which are in most cases "Last name, First name."

Bibliographic details:

  • Article: What is a Keystone?
  • Author(s): Dr. Biology
  • Publisher: Arizona State University School of Life Sciences Ask A Biologist
  • Site name: ASU - Ask A Biologist
  • Date published: January 7, 2010
  • Date accessed: October 18, 2018
  • Link: https://askabiologist.asu.edu/what-keystone

APA Style

Dr. Biology. (2010, January 07). What is a Keystone?. ASU - Ask A Biologist. Retrieved October 18, 2018 from https://askabiologist.asu.edu/what-keystone

American Psychological Association. For more info, see http://owl.english.purdue.edu/owl/resource/560/10/

Chicago Manual of Style

Dr. Biology. "What is a Keystone?". ASU - Ask A Biologist. 07 January, 2010. https://askabiologist.asu.edu/what-keystone

MLA 2017 Style

Dr. Biology. "What is a Keystone?". ASU - Ask A Biologist. 07 Jan 2010. ASU - Ask A Biologist, Web. 18 Oct 2018. https://askabiologist.asu.edu/what-keystone

Modern Language Association, 7th Ed. For more info, see http://owl.english.purdue.edu/owl/resource/747/08/
Keystone Ask A Biologist

Roman arch with a prominent keystone. Image by Sara Fuoco via Wikimedia Commons. 

Be Part of
Ask A Biologist

By volunteering, or simply sending us feedback on the site. Scientists, teachers, writers, illustrators, and translators are all important to the program. If you are interested in helping with the website we have a Volunteers page to get the process started.

Donate icon  Contribute

Share this page:

 

Share to Google Classroom