Domain: Humanities and Social Sciences — Economics
Target concept: Money demand curve: A downward-sloping curve (with the interest rate on the vertical axis)

Video generation prompt: The figure shows a coordinate system, with the vertical axis representing the interest rate and the horizontal axis representing money demand. Data points are plotted, illustrating how money demand changes as the interest rate increases, which represent the money demand curve. These data points are then connected to form a smooth curve.

Evaluation guide:
Target concept: Money demand curve as a downward-sloping functional relationship L = f(i), where i = nominal interest rate (vertical axis) and L = real money demand (horizontal axis), grounded in liquidity preference theory. Minimum mechanistic assumption: Agents rationally substitute away from zero-yield money toward interest-bearing assets as i rises, with no behavioral anomalies or frictions. Expected phenomena storyline: (Phase 1) Clean Cartesian plane appears with correctly oriented/labelled axes; (Phase 2) Data points materialize sequentially in order of increasing i (top-to-bottom) and decreasing L (left-to-right), confirming inverse pairing; (Phase 3) A smooth curve connects them, visually locking the downward slope; (Phase 4) Final frame holds with explicit textual reinforcement (‘↑i → ↓L’). Visibility constraints: All labels must be legible at 720p; curve must dominate visual field; no occlusion; perspective is orthographic (no 3D tilt or depth).

Manual:
I. Basic Demonstration Information
Demonstration Title: Money Demand Curve (Downward-Sloping Relationship Between Interest Rate and Money Demand) Demonstration
Subject: Humanities and Social Sciences - Economics - Macroeconomics
Demonstration Purpose: To visually demonstrate the inverse relationship between the nominal interest rate (vertical axis) and aggregate money demand (horizontal axis) using a standard Cartesian coordinate system; to illustrate how rising opportunity cost of holding idle money reduces desired money holdings; and to reinforce the graphical representation of Keynes's liquidity preference theory.

II. Demonstration Carrier/Equipment
Core Carrier: Static/dynamic vector graphic of a 2D coordinate plane (SVG or high-res raster)
Auxiliary Equipment: Clean white or light-gray background; sans-serif, high-contrast typography (e.g., Arial Bold); consistent color scheme (blue for curve, black for axes, gray for gridlines); optional subtle animation engine for sequential plotting.

III. Demonstration Content Description
Layout: Full-frame centered Cartesian plane. Vertical axis labeled 'Interest Rate (%)' with upward arrow; horizontal axis labeled 'Money Demand (billions $)' with rightward arrow. Origin at bottom-left. Gridlines optional but consistent.
State Control: All elements rendered statically or animated with deterministic timing (no randomness). Curve must be mathematically downward-sloping (dy/dx < 0) and monotonic.
Comparison Baseline: No biological/human carriers — pure graphical demonstration. Reference standard is theoretical correctness: higher interest rate → lower money demand.

IV. Observation of Core Phenomena
Axis Orientation: Vertical axis unequivocally represents interest rate; horizontal axis unequivocally represents money demand. Labels are large, bold, and unambiguous.
Data Pattern: Six data points plotted, showing a clear inverse trend (e.g., (100, 5), (150, 4), (200, 3), (250, 2), (300, 1.2), (350, 0.8)).
Curve Formation: Points connected by a single, smooth, continuous, downward-sloping curve — no kinks, loops, or flat segments. Curve visually dominates the graph.
Visual Verification Features: (1) Downward slope confirmed by eye-tracking path (top-right → bottom-left diagonal dominance); (2) Axis labels match knowledge point verbatim; (3) No competing visual elements (e.g., supply/demand dual curves, equilibrium marker, or shifting curves).

V. Summary of Key Knowledge Points and Principles
Core Concept Definition: The money demand curve expresses the inverse relationship between the nominal interest rate (the opportunity cost of holding money) and the quantity of real money balances households and firms wish to hold — a foundational element of Keynesian macroeconomics.
Economic Principle: As interest rates rise, bonds and deposits yield higher returns, making money (non-interest-bearing) relatively more costly to hold → agents reduce money demand. This yields a downward-sloping curve in (i, L) space.
Further Knowledge: Shifts in the curve (e.g., due to income or price level changes) are distinct from movements *along* the curve (caused solely by interest rate changes). This demonstration shows only movement along the curve.

VI. Demonstration Precautions
Graph Fidelity: Avoid logarithmic or transformed axes; use linear scales only. Do not annotate shifts — only the static curve and its underlying points.
Animation Integrity: If animated, plotting sequence must preserve causal order: interest rate increase → observed reduction in money demand (not reverse). No anthropomorphic agents (e.g., 'people choosing') — pure functional relationship.
Timing Constraint: Total video ≤10 seconds: 1.5s axes, 3s point plotting (0.5s × 6), 1.5s curve draw, 1s freeze on final frame with subtitle, 3s static display with voiceover placeholder (not rendered).

Prompt Grounding rubric:
level_1: No coordinate axes appear anywhere in frame; if axes do appear they are unlabeled or mislabeled (for example money demand on the vertical axis or interest rate on the horizontal axis); no interest-rate/money-demand data points are plotted; no curve is drawn; the frame instead shows something unrelated such as a bar chart, pie chart, or plain text.
level_2: A coordinate grid appears but the axis roles are swapped or mislabeled (for example 'Money Demand' on the vertical axis, or 'Interest Rate' on the horizontal axis); at least one axis has no label at all; a few marks appear on the plane but they are not clearly tied to either axis, and nothing suggests a downward trend.
level_3: The vertical axis is clearly labeled as interest rate and the horizontal axis as money demand, both legible; three or four data points are plotted that roughly move from upper-left toward lower-right (higher interest rate paired with lower money demand); the points are left unconnected, or connected with a jagged, rising, or flat line rather than a smooth downward curve; the numeric scale on each axis is arbitrary but not self-contradictory.
level_4: The axes are labeled 'Interest Rate (%)' (vertical) and 'Money Demand (billions $)' (horizontal); at least five data points appear, tracing a coherent downward-sloping pattern, for example points near (100, 5), (150, 4), (200, 3), (250, 2), and (300, 1.2); the points are joined by one smooth, continuous, downward-sloping curve; small imperfections are allowed, such as a slightly uneven tick spacing or one label sitting a bit off from its axis.
level_5: Everything at level 4 is present, and in addition: the axis labels carry directional arrows ('Interest Rate (%)' with an upward arrow, 'Money Demand (billions $)' with a rightward arrow); six data points are plotted approximating (100, 5), (150, 4), (200, 3), (250, 2), (300, 1.2), and (350, 0.8); the curve through them is a single smooth downward-sloping line with even stroke width and good contrast against the background; gridlines, if shown, are applied consistently; no stray marks, duplicate curves, or unexplained visual artifacts appear anywhere in the frame.

Scientific and Causal Correctness rubric:
level_1: The plotted curve slopes upward or is flat, meaning money demand appears to rise or stay the same as the interest rate rises; on-screen text or labels contradict liquidity-preference theory (for example implying 'higher rates cause more money demand'); nothing in the sequence conveys that money demand and the interest rate move in opposite directions.
level_2: The overall curve trends downward, but one or more plotted points break that trend (for example a point sits higher and further right than the point before it); the axis labels are correct, but the numeric ranges are economically implausible (for example an interest rate axis running from 0% to 2000%); nothing in the sequence clarifies which variable is meant to be driving the other.
level_3: The curve is downward-sloping and every plotted point is consistent with that trend (as interest rate rises, money demand falls, with no reversals); the axis ranges are realistic for an economy (for example interest rate spanning roughly 0-15%, money demand spanning a few hundred billion dollars); nothing in the sequence contradicts Keynesian liquidity-preference theory, even without any extra annotation explaining the causal direction.
level_4: Beyond level 3, the downward slope is strictly monotonic across every plotted point with no flat or reversed segments, the curve is visually emphasized (for example by a bolder or distinctly colored stroke) so the inverse relationship is unmistakable, and the overall steepness of the curve is plausible for interest-sensitive money demand: that is, a given rise in the interest rate corresponds to a noticeably smaller proportional fall in money demand, without requiring any single 'textbook' numeric ratio.
level_5: Beyond level 4, the sequence makes the causal story explicit and correct throughout: each successive point sits both higher on the interest-rate axis and further left on the money-demand axis than the last (never the reverse pairing), the final curve is consistent with agents shifting out of zero-yield money into interest-bearing assets as rates rise, and any on-screen text (for example a closing caption) correctly states that money demand falls as the opportunity cost of holding cash rises, with no simplification or reversal of this logic anywhere in the clip.

Spatiotemporal Consistency rubric:
level_1: The axes are redrawn partway through the clip; the curve appears fully drawn before any axes or points exist; labels pop in at inconsistent sizes or positions; the view jumps abruptly in zoom or pan; the drawing order is reversed, for example a finished curve appearing before the axes it sits on.
level_2: The axes appear first and then the data points, but the points blink into place in no clear order; the curve is drawn in disconnected segments with visible pauses between them; label positions shift between frames; the pacing is uneven, for example a long blank pause followed by everything flashing into place almost at once.
level_3: The full graph stays centered in a fixed frame throughout; the axes are drawn first and hold steady for about a second and a half, then the six data points appear one at a time in sequence (about half a second apart, three seconds total), and only then does the curve animate smoothly through them over about a second and a half; minor unevenness in point timing or label fade-in is acceptable, but nothing teleports and nothing changes scale unexpectedly.
level_4: Beyond level 3, the frame stays stable and centered for the entire clip; the axes draw in about a second and a half with a smooth stroke animation; the six points appear strictly in order of increasing interest rate (moving left-to-right or top-to-bottom, whichever the animation uses) at an even pace of about half a second per point; the curve then draws end-to-end in about a second and a half with smooth easing rather than a constant-speed line; axis and point labels stay legible and anchored in place, with no visible warping or stutter.
level_5: Beyond level 4, the coordinate grid and axis lines look stable and unchanging across the whole clip; each point eases smoothly into its final position on the curve rather than snapping there instantly; the curve's shape is a single smooth downward arc consistent with the plotted points (no kinks or reversals); if a closing subtitle appears, it shows up close to when the finished curve settles into place rather than noticeably before or after; the whole sequence runs no longer than about ten seconds with no dropped frames, flicker, or elements drifting from their intended position.