Grade Levels: 3-5, 6-8

In this lesson plan, adaptable for grades 3-8, students use the drag-and-drop game Build-a-Body: Excretory System to assemble a human excretory system from organs. Case studies challenge students to put their new knowledge of the excretory system to the test.  

Lesson Plan Common Core State Standards Alignments

Lesson Plan Next Generation Science Standards Alignments

Students will:

  1. Identify and learn about the organs that make up the human excretory system.
  2. Build an excretory system using an interactive simulation, and discover how the organs work together.
  3. Review a case study and identify the organ affected by a problem.


  • Computers or other devices with Internet access
  • Interactive whiteboard
  • Small dry erase boards for each pair or small group, or sheets of paper


This lesson plan features the simulation Build-a-Body: Excretory System developed by our partner,  Spongelab Interactive. This playful interactive challenges students to assemble a human excretory system by dragging and dropping associated organs into to the correct place. The interactive also challenges students to case studies in which they read about a problem and then identify the organ affected by the problem   

Preview and play Build-a-Body: Excretory System to plan how you will adapt it to your students’ needs. Review tips on Setting Cooperative Gaming Expectations.

For more information about using interactive simulations effectively in the classroom, review our Educator’s Guide to Teaching with Digital Interactive Models and Teaching Strategies for Interactive Simulations.

Build background knowledge or reinforce topics with these BrainPOP movies: Urinary System, Digestive System, Endocrine System, Muscles, Human Body

Lesson Procedure:

  1. Prompt students to share what they know about the human excretory system, such as the organs that make up the system.
  2. Tell the class that the excretory system is the part of the body that removes waste products. Explain that the the urinary system is one part of our body’s excretory system. Then play the BrainPOP movie Urinary System on the whiteboard or other display.  
  3. After the movie, project the Build-a-Body: Excretory System interactive on the whiteboard. Explain that that today they will explore and assemble a human excretory system. After, they will review a case study in which they must associate a functional problem within the excretory system to the affected organ.
  4. Read, or invite a volunteer to read, the information about the excretory system on the left side of the screen. Then choose, but do NOT click, one of the organs listed in the the tray on the right. Now challenge pairs to come up with a definition for that organ and write it on paper or a small dry erase board. On your signal, instruct each pair to hold up their definitions.
  5. Now click the organ and read the definition that displays on the left side of the screen. Compare the definition to each pair’s definition and award points based on the accuracy of their definitions (e.g., 3 points for a correct and highly detailed definition, 2 points for a correct definition that may be less detailed; 1 point for a partially correct definition, and 0 for an incorrect definition). For more in-depth game play, display all the responses in the front of the room and have the class analyze them together. They can rank the responses in the same way and a volunteer can keep track of each team’s points on the board
  6. After analyzing answers, have pairs work at their own computers or devices to click the organ and drag it to the correct position on the screen.
  7. Model how they can use the arrows to the left of the illustration to move up and down and the plus/minus to zoom in and out.
  8. Repeat the process of defining, comparing definitions, ranking, and dragging/dropping for each organ until the excretory system is assembled.
  9. After pairs build their excretory systems, challenge them to solve the case study.
  10. Bring the class together to reflect on the organs and case study they explored through the interactive. Have them share what new information they learned. You can return to the discussion questions from the beginning to assess what they’ve learned.

Extension Activities:

Invite students to further explore the topic of body systems by watching the following BrainPOP movies: Digestive System, Endocrine System, Muscles, Human Body.

Students may also play other body system Spongelab games, including: Build-A-Body: Nervous System, Build-A-Body: Circulatory System, Build-a-Body: Skeletal System, and Build-A-Body: Digestive System.