How the atlas is wired

This is the Ephemerent Atlas concept map. Every dot is a concept, and every line between them is a claim that one idea is needed before another.

The full map is shown, with three vertical routes of concepts and curved lines running between them. Shows /map.

There are three routes. Mathematics on the left, computing in the middle, physics on the right. They are drawn as separate columns because each has its own order.

Three labelled columns are highlighted in turn, each holding five concepts stacked in order. Shows /map.

Start at the top of mathematics, with quantities, ratios and scale. Nothing else in this column can be read honestly until a number carries a unit.

The topmost mathematics node, quantities ratios and scale, is enlarged and brought forward. Highlights the concept quantities ratios and scale.

Watch the line travel. Quantities and ratios lead into functions as dependence, because a function is a rule that relates one measured quantity to another.

A marker travels along the line from quantities ratios and scale down to functions as dependence. Traces 1 map connection.

The chain continues. Functions lead to vectors and coordinate change, and vectors lead to change and accumulation. Each step is a claim that the earlier idea is load bearing for the later one.

The marker continues down two further lines, through vectors and coordinate change and on to change and accumulation. Traces 2 map connections.

This is not a syllabus order. It is a dependency claim, and every one of these lines carries a citation and a named reviewer you can inspect.

The change and accumulation node is highlighted while the traversed lines remain drawn behind it. Highlights the concept change and accumulation.

Some lines cross between columns. This bridge runs from functions as dependence into procedures and state, because a program is a function you can execute.

A curved bridge line is traced from the mathematics column across into the computing column, while other lines dim. Traces 1 map connection.

And this one runs from vectors into motion and interaction. You cannot describe a force without first being able to describe a direction.

A second bridge is traced from vectors and coordinate change across to motion and interaction in the physics column. Traces 1 map connection.

Follow that bridge and you arrive at a bench. Here the atlas stops describing and starts computing.

The motion and interaction node is highlighted at the end of the traced bridge. Highlights the concept motion and interaction.

A constant net force acts on a cart. Watch the first half of the run, and watch the spacing between the marks.

A cart accelerates from rest along a track. Strobe marks left behind it grow further apart as it travels. Runs the motion model from 0% to 50% of its run.

The gaps grow. Equal intervals of time do not produce equal intervals of distance, because the speed itself is still increasing.

The cart completes its run. The position against time trace curves upward rather than forming a straight line. Runs the motion model from 50% to 100% of its run.

Nothing here was drawn by hand. The numbers come from the same Rust model the lesson uses, and you can open the sample table underneath to check every one of them.

The bench remains on screen with its inspectable table of modelled samples available beneath it. Shows /labs/motion-tape.

That is the shape of the atlas. Concepts, the claims that connect them, and a model at the end of the route that you can run yourself.

The view returns to the full map with every route drawn. Shows /map.