Each section invites children to use equipment to test scientific principles and, at the same time, turn what are often invisible processes into visible ones.

The real state space is summarized into a smaller set of the visible ones.

That left only the visible ones, and there did not seem to be anything large enough here to count as such.

However, such changes need not be visible ones.

Back afloat, our four canoes are the only ones visible.

As the sun goes down, their lights are the only ones visible.

They had apparently put no bonds on her, no visible ones.

No need for the visible ones to be the only ones about.

The crater is one of the most visible ones from Earth.

For a long time these were the only ones visible from the farmhouse.