Food’s Journey Begins

Overview

This 45-minute lesson is the second in a six-lesson unit titled Digestive System Discoveries, designed for Year 4 students. It focuses on understanding the early stages of digestion: mechanical digestion through chewing in the mouth and the beginning of food’s passage down the oesophagus. The lesson engages students with a hands-on simulation activity that brings these concepts to life, aligning tightly with the National Curriculum for England science requirements on the digestive system.

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National Curriculum Links

• Key Stage 2 Science - Animals, including humans
  Pupils should be taught to:

  • describe the simple functions of the basic parts of the digestive system in humans
  • identify the different types of teeth in humans and their simple functions
  • construct and interpret a variety of food chains, identifying producers, predators and prey

• Learning Objectives (Year 4):

  • Understand and describe mechanical digestion in the mouth
  • Explain how food moves from the mouth to the stomach via the oesophagus
  • Use scientific vocabulary accurately (e.g., teeth, saliva, oesophagus, mechanical digestion)
  • Perform a simple scientific investigation and record observations

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Learning Outcomes

By the end of the lesson, pupils will be able to:

• Describe how teeth and saliva work together to break down food mechanically.
• Explain the function of the oesophagus as a muscular tube carrying food to the stomach.
• Demonstrate understanding through a simulated experiment showing chewing and swallowing processes.
• Use labelled diagrams and simple scientific terms to explain the digestion stages covered.

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Resources Needed

• Paper plates (one per group)
• Different types of “food” models (e.g. crackers, grapes, banana slices) to simulate solid and soft food
• Plastic teaspoons (to simulate chewing)
• Clear plastic tubing (to represent the oesophagus)
• Water spray bottles (to simulate saliva)
• Whiteboards and markers for group work
• Lined exercise books for writing and diagrams
• Visual aids: large diagram/ poster of the mouth and oesophagus
• Pre-prepared diagram handouts for labelling

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Lesson Breakdown

1. Starter (5 minutes)

• Engage and activate prior knowledge:
  Begin with a whole-class discussion: “What happens to our food from the moment we put it into our mouth?”
• Recap key terms from lesson 1: mouth, teeth, digestion
• Briefly explain today's focus: chewing (mechanical digestion) and swallowing (the journey through the oesophagus).

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2. Direct Teaching & Demonstration (10 minutes)

• Using a large poster of the mouth and oesophagus, explain:
  • The role of teeth in breaking food into smaller pieces (mechanical digestion)
  • Saliva’s role in moistening food to help swallowing (without going into chemical digestion details yet)
  • The oesophagus as a muscular tube that moves food in waves (peristalsis) down into the stomach.
• Model chewing with the crackers and water spray; explain how chewing breaks food physically.
• Show how the oesophagus works by using clear tubing and pushing soft food “down” to simulate swallowing.

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3. Hands-On Activity (15 minutes)

• Group Task (6 groups of 15 students): "Chewing and swallowing simulation"
  • Each group gets paper plates, “food” items (both hard and soft), plastic teaspoons, and water spray to act as saliva.
  • Students take turns using the spoon to “chew” (break into smaller pieces) pieces of food on the plate, spraying water to "moisten" it.
  • Then, students push the “moistened food” down through the plastic tube, imitating the oesophagus muscle action pushing food to the stomach.
• Circulate to observe, prompt scientific discussion, and ask questions about what happens at each stage.

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4. Consolidation and Discussion (10 minutes)

• Each group shares observations on:
  • How chewing changed the food texture
  • How adding “saliva” helped the food pass down the tube
• Introduce simple questions to discuss as a class:
  • Why is chewing important?
  • What would happen if food didn’t get chewed?
  • Can food move down the oesophagus without swallowing?
• Relate answers back to definitions and function of teeth and oesophagus.

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5. Plenary (5 minutes)

• Quick quiz game on whiteboards (true/false statements):
  • “Teeth mix food with saliva.” (True)
  • “The oesophagus grinds food into smaller pieces.” (False)
  • “Swallowing moves food to the stomach.” (True)
• Recap key vocabulary: mechanical digestion, chewing, saliva, oesophagus, swallowing
• Set simple homework: Draw and label a diagram showing the journey of food from mouth to stomach.

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Assessment

• Informal assessment during group discussions and question sessions.
• Observation of practical activity participation and explanations offered by pupils.
• Responses in plenary quiz.
• Homework diagram labelled with key parts and processes as evidence of understanding.

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Differentiation

• Support:
  • Provide sentence starters for describing the process.
  • Pair lower-attaining pupils with peers for the practical activity.
• Challenge:
  • Ask higher-attaining pupils to explain why saliva is important beyond just moistening.
  • Encourage them to predict what might happen if the oesophagus didn’t work properly.

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Extension Idea (if time/resources allow)

• Introduce simple peristalsis demonstration using a balloon or a sock being squeezed to illustrate muscular movement pushing food.

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This lesson combines clear curriculum objectives with memorable, tactile experiences to embed pupils’ understanding of the early digestive process. By physically simulating chewing and swallowing, students move beyond theory into hands-on discovery, heightening engagement and retention in this crucial stage of human biology.