Semantic primitives

Meaning must survive when the visual form disappears.

These examples are source contracts for public learning content. They do not claim that every historical page has completed manual assistive-technology review.

Math

Readable equation structure.

The visible form uses MathML while the wrapper carries a concise spoken label.

Kinetic energy is Formula: one half m v squared..

Diagram

A visual with an equivalent explanation.

Colour and position support the concept; the caption and long description carry the meaning.

Force direction on a blockA rectangular block sits on a horizontal line. A right-pointing arrow labelled applied force begins at the block. A left-pointing arrow labelled friction begins at the block and is shorter.

Data table

Headers remain navigable.

The scroll container is keyboard-focusable on narrow screens and does not convert table data into visual-only cards.

Example reviewed-content requirements
SubjectTopicPublication boundary
PhysicsKinematicsReviewed source required
ChemistryMole conceptUnits and symbols preserved
BiologyCell structureDiagram description required