What You'll Need

3D-printed parts (base feet + bucket hanger) or equivalent hardware
Steel rods (Ø 4.5 mm × 30 cm, 2 legs + 1 crossbar)
Paint cups (small plastic/metal pots with a fine bottom hole)
Acrylic or finger paints + water (to thin)
Paper, canvas, or cardboard (painting surface)
String or cord (to suspend cups)
Protective mat or tray (to catch splashes)

Safety First!

!Wear an apron and cover work area with newspaper or plastic.
!Use non-toxic, water-based paints safe for skin contact.
!Ensure adult supervision when drilling holes or handling tools.
!Smooth any rough edges on 3D-printed parts before use.

Let's Make It! Step-by-Step Guide

Assemble the Frame

Step 1 of 6

Attach the 3D-printed feet to the two steel leg rods.
Slide the crossbar into the top of both legs, forming an A-frame structure.
Check that the frame sits level and stable on the work surface.

The Science Behind It

A pendulum’s motion is governed by gravity and inertia: it swings in a regular period determined by the rod length. As it swings, paint drips under centrifugal force, tracing arcs and ellipses on the surface. This melding of predictable physics and fluid dynamics yields endlessly unique patterns.

Helpful Tips

Amplitude Control: Wider pushes yield larger loops; smaller pushes create tighter spirals.
Height Tuning: Experiment with 5–20 cm cup-to-canvas gaps for different drip behaviors.
Clean Swaps: Rinse cups thoroughly between colors to avoid muddy blends.
Surface Choice: Try heavyweight paper, stretched canvas, or wood panel for varied textures.

Try These Variations!

1Alternate Swing Modes: Twist the cup before release for spiral or figure-eight patterns.
2Geometry Lesson: Time multiple swings to estimate the period T ≈ 2π√(L/g) in a mini-math activity.
3Non-Traditional Paints: Mix inks, dyes, or even coffee for earthy tones.
4Glow-in-the-Dark: Use fluorescent or glow-in-the-dark paints and view under UV light.

Pendulum Painting