S1·E78 Sand Pendulum
Aired September 24, 1997
Synopsis
The Teletubbies enter their Tubbytronic Dome but then the Magic Windmill starts to spin and the Teletubbies watch three children filling up a soft drink bottle with black and white sand and the sand comes out all over the place. Tinky Winky, Dipsy, and Laa Laa follow Po around Teletubbyland.