No. 51Mateo's marble machine← → step through the guideboard · 73 × 69 cm · 182 holes
Crank0 rpm
Chain0 cm/s
Marbles0 /s
Lap–
Bell0
What this step adds; in part B, the marbles' glint and the bellParts already in placeA toy built from what earlier machines make, drawn in 1 cm units: a board 73 cm wide and 69 cm tall. The crank's 30-tooth gear turns a 15-tooth gear, so the elevator's 12-tooth bicycle sprockets turn twice per turn, and with a cup every 6 links each turn lifts 4 marbles 53 cm. A solid marble that rolls without slipping keeps 5/7 of the energy it gains as forward speed, so after falling h it moves at v = √(2·g·h·5/7): the first ramp's 7.3 cm send it off at 1.0 m/s. One ride round from the top cup takes about 3.8 s. A marble waits in the boot for a cup, so with 20 marbles the lap is 20 ÷ the cups' rate (10 s at 30 turns a minute) until cranking gets ahead of the ride. The model ignores friction, treats each end block as a dead stop and assumes the wheel turns at 300° a second, so real marbles run a little slower. This is a guide to how the parts go together, not engineering drawings. Adults do all the sawing, drilling, turning and casting. Marbles are a choking hazard for children under 3: play with an adult there and keep them away from younger children.