Jump to content

File:Magdeburg hemispheres small.png

Page contents not supported in other languages.
This is a file from the Wikimedia Commons
From Wikipedia, the free encyclopedia

Magdeburg_hemispheres_small.png (245 × 431 pixels, file size: 17 KB, MIME type: image/png)

Summary

Description
English: Drawing of a small pair of Magdeburg hemispheres from 1870s, used for demonstrating atmospheric pressure in natural philosophy classes. About 4-5 inches diameter. Magdeburg hemispheres were invented by Otto von Guericke in 1650. To use, the edges of the hemispheres were greased and pressed together, and a vacuum pump was attached to the port at bottom. When the air was evacuated from the inside, the valve at bottom was closed and the pump detached and the hemispheres would be held firmly together by atmospheric pressure. To demonstrate the pressure, ropes would be attached to the ring at top and a ring that could be screwed into the bottom (not shown), and audience members would be invited to try to pull the hemispheres apart. The force holding them together is equal to the area bounded by the circular joint between the hemispheres, multiplied by the difference between the inside and outside air pressure. For 5 inch hemispheres this would be about 280 lb. Alterations to image: removed figure number, increased brightness, and converted JPG to 32 color PNG.
Date
Source Retrieved 2008-06-27 from Adolphe Ganot & Edmund Atkinson (1872) Natural Philosophy for General Readers and Young Persons, D. Appleton & Co., New York, p.101, fig.90 on Google Books
Author Adolphe Ganot
Permission
(Reusing this file)
Public domain in USA - first published in USA prior to 1923

Licensing

Public domain
Public domain
This media file is in the public domain in the United States. This applies to U.S. works where the copyright has expired, often because its first publication occurred prior to January 1, 1929, and if not then due to lack of notice or renewal. See this page for further explanation.

United States
United States
This image might not be in the public domain outside of the United States; this especially applies in the countries and areas that do not apply the rule of the shorter term for US works, such as Canada, Mainland China (not Hong Kong or Macao), Germany, Mexico, and Switzerland. The creator and year of publication are essential information and must be provided. See Wikipedia:Public domain and Wikipedia:Copyrights for more details.

Captions

Magdeburg hemispheres

Items portrayed in this file

depicts

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current17:22, 27 June 2008Thumbnail for version as of 17:22, 27 June 2008245 × 431 (17 KB)Chetvorno{{Information |Description={{en|1=Woodcut of a small pair of Wikipedia:Magdeburg hemispheres from 1879s, used for demonstrating atmospheric pressure in natural philosophy classes.}} |Source=Retrieved 2008-06-27 from [http://books.google.com/books?id=s

The following page uses this file:

Global file usage