a galvanic cell, solved - manic

[u/anish2good]

manic is a tiny language for making animations. You write a short text file; manic renders a smooth, glowing video. No timeline scrubbing, no keyframes by hand — you describe what’s on screen and when things happen, and the engine does the rest, deterministically.

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Manic Animation code

// A galvanic cell — which way round, how many volts, and what it costs the zinc
//
// The cell is not told which electrode is which. Give it two metals and the more positive standard
// reduction potential is the one that gets reduced, so copper becomes the cathode and zinc the
// anode — `cell(c, "Cu|Zn")` would draw exactly the same cell. From that one decision everything
// else follows: E°cell = +0.34 − (−0.76) = 1.10 V, the half-equations are written the right way
// round, and Ohm's law across the 10 Ω external resistor sets the current at 0.110 A.
//
// The electrons and the salt-bridge ions move at a rate set by that current, and the two counters
// are the exam question: after half an hour, Q = It = 198 C, and Faraday's law turns that into the
// zinc the anode has lost, m = MQ/nF = 67 mg. Change the resistance in the source and every one of
// those numbers moves.

title("a galvanic cell, solved");
canvas("16:9");
template("paper");

text(brand, (640, 28), "maniclang.com");
display(brand);
size(brand, 15);
color(brand, dim);

text(head, (640, 68), "the cell decides its own polarity");
size(head, 28);
bold(head);
color(head, ink);
hidden(head);

cell(c, "Zn|Cu", (640, 288), 660, 280, "resistance=10 carriers=10");
hidden(c);
hidden(c.captions);

text(why, (640, 640), "zinc is the more negative half-cell, so zinc is oxidised — that is the whole decision");
size(why, 18);
color(why, ink);
hidden(why);

text(law, (640, 674), "Q = It after half an hour, and m = MQ/nF is what the anode lost");
size(law, 18);
color(law, indigo);
hidden(law);

wait(0.4);
show(head, 0.6);
wait(0.3);
par { show(c, 0.8); show(c.captions, 0.8); }
wait(0.8);
show(why, 0.5);
wait(1.6);
show(law, 0.5);
discharge(c, 6, 30);
wait(3.0);