Building a Model of the Excretory System

Outcomes:
Students will be expected to • Describe the structure and function of the major organs of the excretory system (302-5).

Materials: • Body diagrams (showing the excretory system) and blank outlines of the human body. • Tag board or other sturdy paper on which to affix the model • Mini-marshmallows • Glue • Kidney beans • Cafeteria Straws • Scissors

• Spaghetti (uncooked) • Red Yarn • Brown paper bags • Blue yarn
Engage:
Open with a class discussion on what the kids know about the Excretory System. What do they know about the Excretory System already?

Explore: Working in small groups, provide each group with a brown bag full of materials that they will need to create their model. Write what each student needs to grab out of the bag. You can also provide this list on the whiteboard or overhead. Each student needs: • 3 kidney beans (kidneys) • 3 spaghetti pieces (urethra) • 2 marshmallows (bladder) • 2 straw pieces (urethra) • 2 pieces of yarn (veins)

One of each item will be used for the key at the top of the tag board. It is helpful to have a model already assembled as a guide for the students.

Explain: To assemble: • Glue the online of the human body onto tag board or heavy construction paper. • Glue the kidney beans in the appropriate place on the human body. Use a diagram of the excretory system to help with this. • The yarn will be approximately 3 inches long. The students will have to separate the yarn into 2 pieces about ½ ways up so that the arteries and the veins go down each leg. Glue on the arteries and the veins. • Insert the spaghetti (broken into approximately 1 inch ling lengths) into the mini-marshmallow at an angle. This represents the ureters