Physics Classroom is making strides to make our site accessible to
everyone, and features many accessibility features.
Our site contains 6 navigation areas. The Primary, Secondary,
and Page Level navigations have a screen reader version of their nav
structure that allows using the left and right keys to navigate sibling
navigation items, and up or down keys to navigate parent or child
navigation items. The others can be navigated using tabs.
Within the main content, we leverage headers to provide in page or
in tool navigation.
Although we are still rebuilding our content to leverage these tools,
our images should have both short and verbose descriptions, the later
describing in great detail the image for those who cannot see. Any
formulas found within the images are often in the image figure below the image.
Equations and formulas are rendered using MathJax, which has both verbal,
braille (including nemath braille), and keyboard navigation within them.
Learn how to configure and leverage this for various screen readers on our
Equation Navigation Page.
While not every area of
Physics Classroom is usable purely from keyboard and screen reader, we
are committed to continue work on making this possible. If you have
questions or need additional help, please use
this link to
contact us
.
The search for the atom began a couple millennia ago. This chapter chronicles a portion of that story from ancient times up to our understanding of a nuclear model of the atom. The chapter discusses the work of Mendeleev and others in developing a periodic table. An emphasis is placed on understanding how the elements can be understood in terms of their subatomic particles. This chapter ends with a discussion of ions and the use of the periodic table in predicting ion charge.