Gilbert’s Marble Course

Gilbert and Leonard make a marble course in the school garden. They join cardboard channels inside a shallow tray.

Gilbert lets the blue marble go from the top. It rolls quickly, then stops where two channels meet.

“There is a bump in the way,” says Leonard. He points to one piece of cardboard sticking up.

Gilbert presses the piece down, but it springs up again. Their teacher brings a small roll of tape.

The boys tape the join so it lies flat. They run a finger over it to check for another bump.

Gilbert tries the marble again while Leonard watches the join. This time it rolls all the way to the end.

They add a gentle bend to make the course more interesting. The marble slows down but keeps moving through it.

Other children come over to take a turn. Gilbert shows them where to start and how to keep the marble in the tray.