How Animal Lungs Work

About this printable How Animal Lungs Work science reading passage, NGSS-aligned (Grades 3-5)

This 250-word reading passage introduces fourth-grade students to how animal lungs work, aligned with NGSS standard 4-LS1-1 and Disciplinary Core Ideas LS1.A. Students learn that lungs are internal organs that take in oxygen from the air and release carbon dioxide. The passage explains the breathing process: when animals breathe in, air fills the lungs and oxygen passes into the blood; when they breathe out, carbon dioxide leaves the body. Students discover why animals need oxygen—to turn food into energy—and learn that different animals have different-sized lungs depending on their body size and activity level. The passage uses simple, age-appropriate language and includes relatable examples to help students understand this essential life process. Audio integration supports diverse learners by providing text-to-speech functionality. Accompanying activities include multiple-choice questions testing recall and comprehension, writing prompts requiring explanation and application, and graphic organizers for visualizing the breathing process and comparing lung structures. The passage is also available in a simplified differentiated version and Spanish translation to support all learners. This resource builds foundational understanding of respiratory systems, preparing students for hands-on investigations and deeper exploration of how organisms obtain and use energy.

Written by Workybooks TeamPublished by Workybooks

Sample passage and quiz from How Animal Lungs Work

Lungs are special organs inside an animal's body that help it breathe. These internal organs (body parts located inside the body) do an important job—they take in oxygen from the air and release carbon dioxide, a waste gas the body doesn't need. Without lungs doing this job, animals could not survive.

When an animal breathes in, air travels into the lungs and fills them up, like blowing air into a balloon. Inside the lungs, oxygen passes from the air into the blood. The blood then carries oxygen to all parts of the body. When the animal breathes out, carbon dioxide leaves the lungs and exits the body. This process happens over and over, all day and all night.

Animals need oxygen for a very important reason. Oxygen helps turn the food they eat into energy that their bodies can use. Without oxygen, animals would have no energy to move, grow, or stay alive. Think of oxygen as fuel that keeps the body's engine running.

Different animals have different-sized lungs. A tiny mouse has small lungs, while a large elephant has huge lungs. Active animals, like cheetahs that run fast, need more oxygen and have larger, more powerful lungs than animals that move slowly.

Interesting Fact: A blue whale has the largest lungs of any animal on Earth—each lung can hold as much air as 1,300 human lungs combined!