The Human Digestive System: Journey of Food

Active learning works for the digestive system because students need to visualize and manipulate the physical process of food changing from bite to waste. When students build models or simulate the journey, they connect abstract labels to concrete experiences, which strengthens memory and corrects misconceptions.

• Year 7
• Science
• 4 activities
• 25 min–45 min

Learning Objectives

1. Identify the sequence of organs food passes through during digestion.
2. Explain the role of mechanical and chemical digestion in breaking down food.
3. Analyze the function of enzymes and bile in the small intestine.
4. Predict the impact of damage to the small intestine on nutrient absorption and overall health.

Simulation Game

⏱ 45 min·Small Groups

Model Building: Digestive Tube

Give groups a long tube, balloons for stomach, and food items like crackers. Students push food through, squeezing at each 'organ' stage to mimic churning and absorption with sponges for villi. Record changes and discuss functions.

Prepare & details

Explain how different organs in the digestive system contribute to breaking down food.

Facilitation Tip: During Model Building: Digestive Tube, provide a pre-cut clear tube set and colored playdough to represent food at each stage, so students can physically push food through and see changes.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Simulation Game

⏱ 30 min·Pairs

Enzyme Experiment: Amylase Action

Pairs mix saliva or amylase with starch solution, test with iodine every 2 minutes for colour change. Graph results and compare to controls without enzyme. Explain how enzymes speed breakdown.

Prepare & details

Analyze the importance of enzymes in the digestive process.

Facilitation Tip: During Enzyme Experiment: Amylase Action, set up multiple test tubes with different starch concentrations and timed iodine drops so students can compare reaction rates and see enzymes at work.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Simulation Game

⏱ 25 min·Whole Class

Simulation Walk: Food Journey

Arrange class in a line as digestive organs. 'Food' students move through, acted upon by organ actions like shaking or enzyme sprays. Narrate and debrief on sequence.

Prepare & details

Predict the consequences for nutrient absorption if the small intestine were damaged.

Facilitation Tip: During Simulation Walk: Food Journey, mark the classroom floor with tape to represent the digestive path and have students walk the route while holding props like a toothbrush or sponge to act out each organ’s job.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Simulation Game

⏱ 40 min·Small Groups

Villi Station: Absorption Demo

Use dialysis tubing as small intestine, fill with starch-glucose mix in sugary water bath. Test contents before and after for absorption. Groups measure and compare to damaged model.

Prepare & details

Explain how different organs in the digestive system contribute to breaking down food.

Facilitation Tip: During Villi Station: Absorption Demo, let students sprinkle colored sugar onto a piece of textured fabric to model villi, then watch how surface area affects absorption speed.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Teaching This Topic

Teach this topic by starting with a simple question: ‘What happens to the sandwich you just ate?’ Use their answers to build a narrative that students test through activities. Avoid overwhelming them with enzyme names or pH values before they grasp the journey. Research shows students grasp digestion best when they connect physical models to function, so prioritize hands-on exploration over lecture.

What to Expect

Successful learning looks like students accurately describing each organ’s role, tracing the food’s state at every stage, and explaining why structure matches function. They should also articulate enzyme function and nutrient absorption without mixing up locations or processes.

Watch Out for These Misconceptions

Common Misconception

During Model Building: Digestive Tube, watch for students who assume digestion happens only in the stomach.

What to Teach Instead

After students push the playdough through the tube, have them pause at each labeled organ and describe what changes occur there, using the model to prove digestion begins in the mouth and continues in the small intestine.

Common Misconception

During Enzyme Experiment: Amylase Action, watch for students who say enzymes are destroyed after breaking down food.

What to Teach Instead

During the experiment, have students observe that the same amylase solution can break down multiple starch samples in sequence, proving enzymes remain unchanged and reusable.

Common Misconception

During Villi Station: Absorption Demo, watch for students who think absorption happens in the stomach.

What to Teach Instead

After the fabric model shows sugar absorption, ask students to compare the fabric’s texture to the stomach lining versus the small intestine’s villi, using the visual to redirect their understanding.

Assessment Ideas

Exit Ticket

After Model Building: Digestive Tube, distribute a blank diagram and ask students to label the organ where most nutrient absorption occurs and explain how its structure supports this function.

Quick Check

During Simulation Walk: Food Journey, call out stages like ‘after chewing’ or ‘after small intestine digestion’ and have students hold up one, two, or three fingers to show the food’s state, then discuss their choices as a class.

Discussion Prompt

After Villi Station: Absorption Demo, pose the question: ‘If a person’s villi were flattened, what problems might they face and why?’ Facilitate a discussion on surface area and nutrient uptake.

Extensions & Scaffolding

• Challenge students to design a ‘digestive system comic strip’ that shows food’s journey with correct labels and speech bubbles explaining each organ’s role.
• For students who struggle, provide a partially filled diagram with missing labels and have them complete it while referencing their tube model.
• Deeper exploration: Ask students to research how one digestive disorder (e.g., celiac disease, lactose intolerance) affects nutrient absorption and present findings to the class.

Key Vocabulary

Peristalsis	The wave-like muscular contractions that move food through the digestive tract, like squeezing a toothpaste tube.
Enzymes	Biological catalysts, specific proteins that speed up chemical reactions, such as breaking down large food molecules into smaller ones.
Villi	Tiny, finger-like projections lining the small intestine that significantly increase the surface area for efficient nutrient absorption into the bloodstream.
Bile	A fluid produced by the liver and stored in the gallbladder that helps to emulsify fats, breaking them into smaller droplets for easier digestion.