Wondercat's curiosity about his own whiskers leads him to investigate animal senses. He discovers how whiskers and other senses help animals understand their surroundings, find prey and avoid danger.

Wondercat discovers that sand is made from tiny pieces of rock. By examining beaches, wind, and water, he learns how sand is formed, moved, and collected into beaches and dunes.

Wondercat has seen pictures of the Moon and knows that grass does not grow on its surface. Through his observations, he learns that plants need water, minerals, air, and sunlight to grow and imagines how grass might be grown on the Moon.

When Wondercat loses his balloon, his observations introduce him to the nature of Earth's atmosphere. He learns about gases, what it means to be lighter than air, and what happens as a balloon rises through the atmosphere.

Fascinated by the pattern and structure of a spider's web, Wondercat investigates why spiders spin them. He learns how spiders use their webs and silk in different ways and discovers where the remarkable threads come from.

After falling from a tree, Wondercat wonders why things fall down instead of up. His investigation introduces him to gravity, weight, and the forces that hold objects in place, before exploring how gravity acts in space.

During a thunderstorm, Wondercat wonders what happens to rain after it falls. He learns how water runs into rivers and oceans, sinks into the ground, or evaporates into the air to form clouds and eventually fall as rain again.

Wondercat learns that although whales are the biggest animals, they are not the biggest living things. To his surprise, his investigation leads him to trees and reminds him that plants are living things too.

Wondercat investigates what clouds are and learns how water evaporates and condenses to form them. He discovers how clouds produce rain and snow, explores changes of state, and learns that frozen water from a cloud can eventually become something solid enough to sit on.

Wondercat investigates rocks and discovers that they are made of different minerals with different properties. He learns about the structure and composition of rocks and minerals and explores some of the many ways people use them.

A beautiful night sky inspires Wondercat to search for the brightest star. He learns the difference between stars and planets and discovers that the Sun is the brightest star in our sky, while exploring sunlight, shadows, day, and night.

Flying looks like fun to Wondercat, but his homemade wings prove useless. He discovers that flight is one of the many ways animals move and learns how it helps them find food, travel, and escape from enemies.

A trip to the desert teaches Wondercat that appearances can be deceiving and that deserts do receive rain. He discovers what happens to desert rainfall and learns how plants and animals adapt to survive with very little water.

Wondercat's curiosity about dinosaurs leads him to an archaeological site and a museum, where he learns about fossils and discovers that dinosaurs came in many different sizes. Comparisons with modern animals help him understand these extinct creatures.

Wondercat learns about seed plants while time-lapse photography shows the roots of a young plant growing downward and its stem growing upward toward the air and sunlight. He learns what plants need to grow, how flowers form, and how flowers produce fruit.