Accessibility
We want every lesson to be usable by every student and teacher. This page says what we do, what we test and what is not right yet.
What the lessons do
- Keyboard. The lesson player works without a mouse: arrow keys or Page Up and Page Down move through slides and diagram steps, F opens full screen, N shows or hides teacher notes, and every button can be reached with Tab.
- Screen readers. Every diagram has a written description, read out with the slide. The full text of every slide, with those descriptions, is on the page under “Slide by slide”. Quiz feedback is announced when you check an answer.
- Reduced motion. If your device is set to reduce motion, diagrams appear finished, with no moving arrows or transitions. Anyone can also pause moving diagrams with the pause button under the slide.
- Without JavaScript. Lessons still read from top to bottom: every slide, every diagram in its finished state, and every quiz answer behind a “Show the answer” link.
- Small screens. On phones, slides change shape: the diagram sits above the text, and text stays at a readable size instead of shrinking inside a tiny slide.
- Reading. Text uses Atkinson Hyperlegible Next, a typeface designed by the Braille Institute to be easy to tell letters apart. Colours are chosen for contrast, and colour is never the only way information is shown.
What we test
Before a release we check the main pages at phone, tablet and desktop widths for overflow and readable text, step through lessons by keyboard, and check that reduced-motion settings show finished diagrams. We aim to meet WCAG 2.2 at level AA.
Known gaps
- Downloadable PDF and PowerPoint files are not yet fully tagged for screen readers. The same content is on each lesson page as text.
- Interactive diagrams are newest on the Photosynthesis lesson; other lessons still use slide pictures for some diagrams, with text alternatives.
- We have not yet had an independent accessibility audit.
Tell us about a problem
If something does not work for you, please contact us with the page address and what happened. We will look into it.