Welcome to the Critical Zone

What makes life on Earth possible? That’s the big question behind the “Welcome to the Critical Zone” exhibit. Scientists use the term “Critical Zone” to describe the thin layer on the surface of the Earth that supports life – that layer extends from the top of the trees down through the soil and groundwater to bedrock. We live in the Critical Zone and we depend on it for the air we breathe, the water we drink, and the food we eat.

Thanks to a grant from the National Science Foundation (NSF), the University of Arizona is home to a Critical Zone Observatory that brings together scientists from many different Earth Science disciplines to study this zone. Geologists, soil scientists, hydrologists, ecologists, microbiologists, and many others all study the same field research sites. Come explore the exhibit and discover Critical Zone science. Journey from the tops of the tree canopy down through the layers of the Critical Zone, from the surface where we live alongside plants and animals, down into the soil that is full of microbes, and below that into the Deep Critical Zone where groundwater circulates and microbes help break down rocks into soil.

On this journey through the Critical Zone, interactive exhibits and games spark critical thinking and engage kids and families with the science. It’s fun, informative, and fascinating!