Thirty-six of them, and none is a video
Numbers you can push around
Set the values, run it, and watch what the equations actually do. Nothing here is animated or pre-recorded: every curve is solved while you move the slider, which is why you can put in a figure nobody planned for and still get the right answer.
Four subjects
36 simulationsThose four numbers are the folders on disk at the last build, not a target. If one of them grows, this page is wrong until it is rebuilt.
Why it is not a video
A recording cannot be asked a question.
An animation shows you one run of one experiment, chosen by whoever made it. Ask it what happens at forty-one degrees instead of forty and it has nothing to say. These are solved on every movement from the same few lines of mathematics the lesson is about — so the awkward value, the one a pupil actually asks about, is answered exactly like the tidy one.
It runs in the browser
No install, no plug-in, no account. Open the page and it is there, on the school's tablets as readily as on yours.
It runs offline
Once the page has loaded, the network is not needed again. A lesson does not stop because the school's connection did.
It is the same engine
These are the figures from inside the textbooks, lifted out and given their own page. Nothing was rebuilt to put them here.
Try one now
The slider above is a small one, written for this page. The real ones go considerably further: a ray tracer you can put a lens in front of, a titration that finds its own equivalence point, a punnett square that rolls the dice rather than listing the outcomes.