Prompted by Keiraville Community Preschool's Earth Hour program, four-year-old Liberty Baines has encouraged her family to take part in the global campaign to switch off lights and power points.

More than just caring for the environment, mum Belinda Baines said the event was about instilling values of gratefulness in her children, Liberty and Henry.

"We talk about other parts of the world and how other families don't have electricity and plumbing," she said.

"After Earth Hour we show them footage of lights being turned off in Sydney, London and New York ... for them to grasp what's happening globally," she said.

The mother of two praised the Keiraville Community Preschool for teaching children they could make a difference.

Preschool director Margaret Gleeson said Earth Hour helped children feel part of a larger caring global community.