The Amazing Body Filter: Your Urinary System!

Materials Needed:

• Playdough (two colors, e.g., red for kidneys, yellow for bladder) OR 2 kidney bean shapes cut from red paper/felt and 1 circle from yellow paper/felt
• 2 straws or pieces of string/yarn (for ureters)
• 1 small balloon or a small plastic bag (for the bladder, if not using playdough/paper)
• 1 shorter straw or piece of string/yarn (for the urethra)
• A large sheet of paper or whiteboard
• Markers or colored pencils
• Optional: A diagram of the urinary system for reference (teacher can sketch this)
• Optional: Water and a clear cup with a coffee filter and some sand/dirt for a quick filtration demo

Lesson Activities (40 minutes):

1. Introduction: The Great Water Mystery! (5 minutes)

Ask Cora: "Have you ever wondered what happens to all the water you drink? Where does it go, and why is it so important to drink water?" Briefly discuss her initial thoughts. Introduce that today she's going to become a 'Body Engineer' to figure out one of the body's amazing cleaning systems: the urinary system!

2. Activity 1: Build Your Own 'Waterworks'! (15 minutes)

Explain that the urinary system is like the body's water treatment and waste removal plant. Guide Cora to build a model of the urinary system on the large paper, explaining each part as you go:

• Kidneys (x2): "These are your body's super filters! Let's make two bean-shaped kidneys using red playdough or paper. Place them on your paper, one on each side of where a spine would be." Function: Filter waste products and excess water from the blood to make urine.
• Ureters (x2): "These are like tiny tubes or slides. Use the two longer straws or strings to connect one from each kidney, leading downwards. These are the ureters." Function: Carry urine from the kidneys to the bladder.
• Bladder (x1): "This is like a stretchy storage bag. Use yellow playdough or the balloon/plastic bag/paper circle to make the bladder. Connect the ends of the ureters to the top of the bladder." Function: Stores urine until you're ready to go to the bathroom.
• Urethra (x1): "This is the exit tube. Use the shorter straw or string connected to the bottom of the bladder, leading off the paper." Function: Carries urine from the bladder out of the body.

As Cora builds, ask her to repeat the name and main job of each part.

3. Activity 2: How It All Works & Teamwork! (10 minutes)

Review the model. Trace the path of water/waste: blood goes to kidneys, kidneys filter it, waste (urine) travels down ureters to bladder, bladder stores it, then urine exits through urethra.

Discussion - System Teamwork: "The urinary system doesn't work alone! It's a team player. How does it work with other systems?"

• Circulatory System: This is its main partner! The heart (circulatory system) pumps blood all around your body, including to your kidneys. The kidneys then clean this blood, taking out waste and extra water. So, the circulatory system DELIVERS the blood, and the urinary system CLEANS it. (Optional demo: Pour dirty water (water with sand/dirt) through a coffee filter into a cup. The filter is like the kidney, the dirt is like waste, and the clean water is like cleaned blood returning to the body).
• Nervous System: Your brain (nervous system) tells your bladder when it's full and when it's okay to empty it.
• Muscular System: Muscles help control the bladder.

Focus on ensuring Cora understands the kidney-blood filtering connection for the learning objective.

4. Activity 3: The Journey of 'Wally the Water Droplet' (5 minutes - can be completed after lesson)

"Now that you're an expert, let's get creative! Imagine you are 'Wally the Water Droplet' who just got drunk by someone. Your mission is to write a very short story or draw a 3-4 panel comic strip about Wally's journey through the urinary system. Where does Wally go first? What does he see? How does he leave?"

Encourage Cora to use the parts of her model in her story/comic. This activity helps her apply her knowledge creatively.

5. Wrap-up & 'Clean Sweep' Review (5 minutes)

Quick review. Point to parts on her model and ask Cora:

• "What's this part called?"
• "What's its main job?"
• "How do the kidneys help keep your blood clean?"
• "What's one other body system the urinary system works with?"

Congratulate Cora on becoming a Urinary System Engineer!

Extension Ideas (Optional, if time or interest allows):

• Research fun facts about the urinary system (e.g., how much liquid the bladder can hold).
• Discuss foods and drinks that are healthy for the urinary system.