Teacher sheet · Ages 10–11 · about 45–50 minutes
The digestive system
Lesson page: echoesof.science/school/digestion/ages-10-11/ · Pupil worksheet: echoesof.science/school/digestion/ages-10-11/print/
Learning aims
- Name the organs of the digestive system in order and describe their main jobs.
- Know that enzymes, acid and bile help break food down.
- Plan and carry out a fair test with repeats and means.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Starter: what is the longest part of the digestive system? |
| 10 min | Read the text; label a digestive system diagram. |
| 20 min | Sugar-cube fair test. |
| 5 min | Game: Which organ? |
| 5 min | Quiz. |
Materials for the experiment
- Sugar cubes (all the same brand and size)
- Three clear cups
- A measuring jug
- Water at room temperature
- A spoon and a saucer for crushing
- Stopwatch
Safety: Do not eat or taste the sugar. Use room-temperature water, not hot water. Wipe up spills so nobody slips.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| The stomach does most of the digestion and absorption. | Most digested nutrients are absorbed in the small intestine. |
| Bile is an enzyme. | Bile helps digest fats by breaking them into small droplets; enzymes such as lipase then digest them. |
| The large intestine is longer than the small intestine. | It is wider, but only about half as long. |
Worksheet answers
- Mouth, oesophagus, stomach, small intestine, large intestine.
- The liver makes bile (stored in the gallbladder), which helps digest fats; the pancreas makes juice with enzymes that break down carbohydrates, fats and proteins.
- Example: whole cube about 120 s, 4 pieces about 80 s, crushed about 30 s: the smaller the pieces, the faster it dissolved.
- Same amount of water at the same temperature, same brand and size of cube, same stirring, same way of judging 'dissolved', three repeats.
Quiz answers
- What is peristalsis? Waves of muscle squeezing that move food along. Food moves through the digestive tract by peristalsis.[1]
- Which enzyme in the stomach starts digesting protein? Pepsin. Pepsin digests protein in the stomach.[2]
- What does bile help to digest? Fats. Bile from the liver helps digest fats.[1]
- Where do most digested nutrients pass into the blood? The small intestine. The small intestine walls absorb nutrients into the blood.[1]
- What do villi do? Give the small intestine a much bigger surface. Villi and microvilli increase the surface area.[2]
- What is one job of the large intestine? Absorbing water. The large intestine absorbs water and forms stool.[1]
Going further
Make a 'gut rope': cut string about 3 m long for the small intestine and about half that for the large intestine, and lay them out across the classroom.
Sources used in this lesson
- [1] Your Digestive System & How It Works (National Institute of Diabetes and Digestive and Kidney Diseases (NIH, USA)): reliability High
- [2] Concepts of Biology, 16.2 Digestive System (OpenStax, Rice University): reliability High
- [3] Anatomy and Physiology, 23.5 The Small and Large Intestines (OpenStax, Rice University): reliability High
- [4] Biology for AP Courses, 25.3 Digestive System Processes (OpenStax, Rice University): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/digestion/sources/
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