Session 1 · VOICE: Investigate
Digestion in a bag
- 10 minDraw what you think happens to a sandwich from mouth to toilet. Compare drawings and list the organs everyone included.
- 25 minModel it: crush crackers and banana in a zip-lock bag (teeth), add water (saliva) and orange juice (stomach acid), squish (stomach churning), then squeeze it through a stocking (small intestine) over a cup.
- 10 minMeasure out a string the length of an adult's gut (about 5–9 m). Where does the small intestine end?
- 5 minMatch each step of the model to the real organ.
Session 2 · VOICE: Investigate
The kiwifruit and jelly test
- 10 minPlan: does fresh kiwifruit stop jelly setting? What about canned kiwifruit or pineapple, or kiwifruit that has been boiled? Write predictions.
- 20 minSet up cups of warm jelly (teacher-poured) with fresh, canned and boiled fruit and one plain control. Leave them in the fridge.
- 15 minRead about enzymes: special proteins that speed up breaking food apart. Actinidin in kiwifruit breaks down protein, and gelatine is a protein.
- 5 minRecord your predictions and reasons in your journal.
Getting started
Use the organ cut-outs to place on a body outline before modelling.
Stretch
Find out how villi increase the surface area of the small intestine and estimate how big it would be if it were flattened out.
Checkpoint
Every group has a set-up enzyme test with a control and written predictions.
Activities for this week
- Digestion in a bag: What happens to food on its journey through your body?
- The kiwifruit and jelly test: Can an enzyme from kiwifruit digest protein?
Useful this week
- The human digestive system ↗ Each organ and its job, to check your digestion model against.
- Fruit enzyme uses ↗ Why kiwifruit and pineapple stop jelly setting, and how enzymes are used in food.
- Seed dispersal ↗ Wind, water, animals and explosions: how seeds travel, including native ones.