food_digestion

Key Stage 3 Science

“Food and Digestion Unit”

“Food and Digestion Unit” From KS2: Statement Sc2 1a Sc2 2a Sc2 2b Sc2 2c

Description That the life processes common to humans and other animals include nutrition, movement, growth and reproduction. About the functions and care of teeth. Food for activity and growth, and the importance of an adequate and varied diet for health. That the heart acts as a pump to circulate the blood through vessels around the body, including through the lungs.

Unit Overview: Establish prior learning: o o

The seven life processes Human organs

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Consider how organs work together forming organ systems. Explain the functions of different organ systems. Focus on digestive system – structure and function.

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Consider the components of a healthy diet and what these components are used for.

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Explain where the different components are digested, using knowledge of enzymes.

‘Food and Digestion’ [LESSON 1] Big Question: Could a human live without a stomach?

Science content State the names and locations of the main human organs. Explain how these organs work together to enable humans to carry out the seven life processes.

Lesson Objectives Science skills

Transferable skills Collaborate with others to work towards common goals (PLTS). Work with others (SEAL).

Key Words Brain; Breathing System; Circulatory System; Digestive System; Excretory System; Heart; Intestine; Kidneys; Liver; Lungs; Nervous System; Organ; Organ System; Stomach Resources: Laminated posters of human torso with laminated organs and labels. Blue tack. Human torso model. Worksheets – Human Body outline and Human Organs to stick onto outline. Organ Systems Wordsearch. Scissors, glue and colouring pencils. Lesson Plan STARTER 1. Students work in groups to stick organs and labels in the correct positions on the human torso. Observe students to assess prior learning. [5 mins] 2. Discuss names and locations of organs, using human torso model to show 3D version of organs. [5 mins] MAIN

1. Using worksheets (‘Human Body’ and ‘Human Organs’), students work individually to cut out organs and stick in the correct place on the human body and label. [15 mins] 2. Ask students for the names of the seven life processes (MRS GREN/NERG). Ask students which organs enable the human body to carry out the process of ‘nutrition’. Students colour the organs on their worksheet that carry out ‘nutrition’ in the same colour. Tell students to discuss in pairs which organs they think are needed for the processes of ‘respiration’ and ‘excretion’. Take feedback and tell students to colour organs appropriately. [15 mins] 3. Introduce the term ‘organ system’ and ask students if they know the name of the system that carries out the process of ‘nutrition’. Add a key to worksheet to show which organs are parts of each system. [10 mins] PLENARY 1. Students complete worksheet ‘Organ systems wordsearch’. [10 mins]

Assessment Opportunities Observing students during starter activity. Listening to and responding to ideas during discussions.

Notes

‘Food and Digestion’ [LESSON 2] Big Question: Could a human live without a stomach? Lesson Objectives Science content Science skills State which organs make up Use an existing model or the digestive system and analogy to explain a describe their functions. phenomenon.

Transferable skills Assess themselves and others, identifying opportunities and achievements (PLTS). Invite feedback and deal positively with praise, setbacks and criticism (PLTs). Give and receive feedback – as individuals, class or group (SEAL).

Key Words Anus; Appendix; Gullet; Gut; Faeces; Large Intestine; Rectum; Small Intestine; Stomach Resources: Worksheets – Comic Strip, The Digestive System. Scissors and glue. Laminated cards – Sequencing Digestion. Food sample, equipment to model journey through digestive system (see teacher’s instruction sheet – ‘Modelling the Digestive System’). Lesson Plan STARTER 1. Explain that we are now focusing on one organ system – The Digestive System. 2. Assess students’ current understanding of digestion. In pairs students complete a comic strip to explain what they think happens during digestion. [10 mins]

MAIN 1. Ask some groups to explain their comic strips to the rest of the class. Ask the rest of the class questions on each presentation, to which they can indicate whether they agree with the ideas suggested by holding up green, orange or red cards. [10 mins] 2. Link the ideas discussed back to the organs identified last lesson - ask students for the names of the main organs that make up the digestive system. Additional organs that were not discussed in the previous lesson may need to be added. Write the organ names on the board. [5 mins] 3. Give students worksheet ‘The Digestive System’. Students label the organs of the digestive system and match organ names to functions. [10 mins] 4. Model the journey through the digestive system (see sheet ‘Modelling the Digestive System’ for suggestion of how to do this) – ask for student volunteers to help at various stages of the model. Question students throughout. [15 mins] PLENARY Give students sets of cards and ask them to sequence them to explain what happens during digestion. [10 mins]

Assessment Opportunities Listening and responding to ideas during discussions. Observe students during card sort activity.

Notes At this stage of the unit, students will not have covered the food groups, therefore only refer to enzymes as helping to break food down. Enzymes will be covered in detail later in the unit.

Comic Strip to Explain Digestion

Modelling the Digestive System Equipment: Plastic funnel Long balloon, end cut off Rubber glove, one finger cut off 30cm hose/rubber tube One leg of a pair of tights Large beaker Tape and scissors Clothes pegs Spoon Brown coloured cereal, milk, juice Diagram:

Sequencing Digestion

Food goes into the mouth. The teeth chew the food. The food is mixed with saliva.

When we swallow, the food goes down the gullet to the stomach.

In the stomach, the food mixes with acid and enzymes. The acid and enzymes help to break down the food.

The food leaves the stomach and goes into the small intestine. It is mixed with more enzymes to break it down even more. Useful substances from the food pass into the blood.

Food that we cannot digest goes from the small intestine into the large intestine. Here water passes out of the undigested food into the blood.

Undigested food from the large intestine is stored. This solid waste passes out of the anus.

The Digestive System On the diagram below, write in the name of the organ that each line is pointing to. Use these words: rectum

small intestine

stomach

mouth

gullet

large intestine

Now cut out the boxes at the bottom of the page showing the functions of these organs. Stick the correct box underneath the correct organ name.

Water is absorbed here. More enzymes are added here, to complete digestion. The soluble food is absorbed.

Faeces are stored here.

Takes food to the stomach.

Food is ground up here and mixed with saliva.

The food is churned up with strong acid here and enzymes.

‘Food and Digestion’ [LESSON 3] Big Question: What is in a slice of bread?

Science content State the names of the seven components of a balanced diet and provide examples of foods that are good sources of starch and sugar. Explain how foods can be tested for the presence of starch and sugar.

Lesson Objectives Science skills Describe and record observations systematically.

Transferable skills Support conclusions, using evidence (PLTS). Work with others, e.g. to investigate, experiment (SEAL).

Key Words Balanced Diet; Benedict’s solution; Carbohydrate; Diet; Fat; Fibre; Iodine; Mineral; Protein; Starch; Sugar; Vitamin; Water Resources: Questions and score grid for Healthy Eating Questionnaire. Food samples. Equipment for starch and sugar food tests. Lesson Plan STARTER 1. Ask students questions from the Healthy Eating Questionnaire. Students record yes/no answers. 2. Read out score for each question, students calculate their total score. 3. Explain what scores mean. Ask students to give indication of score using red, orange and green cards. [15 mins] MAIN 1. Discuss certain questions from questionnaire and obtain names of food groups from discussion. E.g. Ask students why they would not score well if they eat chocolate

every day – fat content; why they would score well if they eat fruit every day – vitamin content. Write names of food groups on board. Students record in a table with two columns – ‘food group’ and ‘good sources’. Leave ‘good sources’ column blank to complete later. [10 mins] 2. Provide students with method for starch and sugar tests. Explain that they will carry out tests to find out whether certain foods contain these carbohydrates. Ask students to suggest what columns they will need in a results table. Draw table on board for students to copy. [5 mins] 3. Students carry out food tests and record results. (Shorten practical if necessary by giving each group of students a different food sample to test and pool results). [20 mins] PLENARY 1. Obtain feedback from students. Discuss whether results were as expected. 2. Fill in carbohydrate – starch and sugar – rows in table to show good sources of these groups. Discuss other good sources. [10 mins]

Assessment Opportunities Listening and responding to ideas during discussions. Observing students during practical, questioning individuals/groups.

Notes

Healthy Eating Questionnaire Questions 1. Do you usually eat breakfast? 2. Do you eat cereal for breakfast? 3. Do you have a drink before you come to school? 4. Do you eat any fruit at breaktime? 5. Do you eat crisps at breaktime? 6. Do you eat chocolate or sweets at breaktime? 7. Do you drink a fizzy drink at breaktime? 8. Do you usually eat chips for lunch? 9. Do you usually eat a cake or burger for lunch? 10. Do you usually eat some chocolate at lunchtime? 11. Do you usually eat a piece of fruit at lunchtime? 12. Do you eat sandwiches for lunch? 13. Do you eat brown/wholemeal bread? 14. Do you eat any fresh vegetables during the day? 15. Do you eat any fresh fruit during the day? 16. Do you eat some meat or cheese during the day? 17. Do you eat cakes every day? 18. Do you eat sweets every day? 19. Do you add extra salt to your food? 20. Do you drink some milk every day? Score Grid Start with a score of 25. Add or subtract points for each ‘yes’ reply, following the grid below: 1

+1

2

+2

6 7

3 4 5

+1 +2 –1

8 9 10

–3 –1 –3 –1 –2

11 12

+2

+2

+1

16 17

13 14 15

+1 +3 +2

18 19 20

–2 –1 +1

–1

Scores: 10-20 You need to think about what you’re eating. To stay healthy you need to cut down on all that fattening food and eat much more fresh fruit and vegetables. 20-30 Your diet is fairly well balanced but don’t be tempted by the fattening foods, even if they look glamorous. 30-40 You are eating on the right lines to stay fit. Make sure you get enough of the right foods and don’t be tempted to lose too much weight. ‘Food and Digestion’ [LESSON 4]

Big Question: What is in a slice of bread?

Science content Provide examples of foods that are good sources of protein and fat. Explain how foods can be tested for the presence of protein and fat.

Lesson Objectives Science skills Describe and record observations systematically.

Transferable skills Support conclusions, using evidence (PLTS). Work with others, e.g. to investigate, experiment (SEAL).

Key Words Balanced Diet; Biuret solution; Carbohydrate; Diet; Fat; Fibre; Mineral; Protein; Starch; Sugar; Vitamin; Water Resources: Food samples. Equipment for protein and fat tests. Lesson Plan STARTER Write the key words below on the board and tell students that they are going to play ‘splat’. [10 mins] Procedure - Ask two volunteers to stand facing each other on either side of the words. - Invite another student to define one of the key words without using it. - The winner is the first volunteer to splat the correct key word with their hand. - The winner should stay on and the student who defined the key word should replace the other volunteer. Key words: protein, fat, carbohydrate, vitamins, fibre, minerals, iodine, starch, sugar, balanced diet. MAIN

1. Recap the work from the previous lesson on testing for starch and sugar. Explain that during today’s lesson students are going to test for fat and protein using the same food samples as before. [5 mins] 2. Provide students with method for protein and fat tests. Ask students to design their results table, using previous lesson’s work as a guide. [10 mins] 3. Students carry out food tests and record results. (Shorten practical if necessary by giving each group of students a food sample to test and pool results). [20 mins] PLENARY 1. Obtain feedback from students. Discuss whether results were as expected. 2. Fill in protein and fat rows in table to show good sources of these groups. Discuss other good sources. 3. Discuss good sources of remaining food groups – fibre, water, vitamins and minerals – and record in table. [15 mins]

Assessment Opportunities Listening to and responding to ideas during discussions. Observing students during practical, questioning individuals/groups.

Homework Tell students to collect the labels from seven foods – each one high in at least one of the seven nutrients needed by the body. Bring to next lesson. (If they are unable to collect the label they should record information in their books and bring a picture of the food).

Notes

‘Food and Digestion’ [LESSON 5] Big Question: Why do we need to eat?

Science content Explain what the main components of a balanced diet are used for.

Lesson Objectives Science skills

Transferable skills Plan and carry out research (PLTS). Provide constructive support and feedback to others (PLTS). Communicate with others (SEAL).

Key Words Balanced Diet; Carbohydrate; Diet; Fat; Fibre; Mineral; Protein; Starch; Sugar; Vitamin; Water Resources: Large sheets of paper. Glue. Pictures of different foods. Access to computers with Internet. Lesson Plan STARTER Prepare a classroom display as a collage to show examples of foods which are good sources of each of the seven nutrients. Use the labels collected by the class for their last homework, as well as the pictures to give extra support. Students could be given the opportunity to explain their homework labels and where they fit in. [10 mins] MAIN 1. Split students into 7 groups and tell them to carry out research into a particular food group - give each group a different group to research. They should find out what it’s needed for, how much is needed, where it can be found, etc. Say that they

can use diagrams to help explain their ideas. Explain that, at the end of the lesson, each group will be asked to present their findings to the rest of the class and that every student must play some part in the presentation. [20 mins] 2. Ask each group to present their findings. Other pupils should peer assess each one and pick out three strengths and one feature which could have been improved. (Be careful to ensure that the criticism isn’t about the students themselves, but about the content of their presentations.) [20 mins] PLENARY 1. Ask students to help complete a summary on the board – table with columns for food group, how much is needed, what it is needed for. (This could be done after each group’s presentation). 2. Students record summary. [10 mins]

Assessment Opportunities Peer assessment – students comment on each group’s presentation.

Homework Design a menu to show the food which a specified person should eat in a single day to stay healthy. Give different students different types of people (e.g. an elderly man, a pregnant woman, a runner, a toddler, a builder, a vegetarian, a Hindu). Tell pupils to think about what that particular person needs which makes them different, and then what foods would be appropriate to provide for those needs. Students should record everything that the person would eat and drink during a single day.

Notes

‘Food and Digestion’ [LESSON 6] Big Question: Why does bread taste different after chewing?

Science content Explain where each food group is digested, with reference to action of enzymes.

Lesson Objectives Science skills Use an existing model to explain a phenomenon.

Transferable skills Support conclusions,using reasoned arguments and evidence (PLTS).

Key Words Absorbed; Amylase; Blood; Carbohydrase; Enzyme; Lipase; Protease; Salivary Gland; Small Intestine; Stomach Resources: Laptop connected to Internet and interactive whiteboard. Model small intestine – Visking tubing, starch solution, amylase, water bath, equipment for starch and sugar tests. Worksheet – Digestion a recap

Lesson Plan STARTER 1. Invite volunteers to play ‘Digest Quest’ game (located on websitehttp://www.teachnutrition.org/default.aspx?SectionId=176) on interactive whiteboard to review path through digestive system. 2. Review components of balanced diet with questioning. [15 mins] MAIN 1. Show models/pictures of starch, sugar, protein, fat, vitamins, and minerals. Discuss the differences between them, e.g. sugar, vitamins, and minerals consist of small individual molecules, whereas starch, protein, and fat all consist of long complicated molecules. Ask students where in the digestive system food is absorbed. Discuss structure of small intestine including presence of villi. Ask students to predict and

explain which molecules would be easily absorbed. Discuss the role of fibre in the diet and explain that our bodies are unable to break this down, so it is passed out of the body as faeces. [10 mins] 2. Explain the model small intestine and set up as a demonstration. Leave apparatus for 20 mins. [5 mins] 3. Meanwhile, explain the role of an enzyme – acting like a pair of scissors to cut up large chain molecules into smaller soluble ones. Show the model/pictures of starch, protein and fat molecules again and say the scissors (amylase/protease/lipase) break them down into glucose, amino acids and fatty acids. All of these small molecules are soluble and can be absorbed into the bloodstream. Draw diagrams to illustrate. Discuss whereabouts in the digestive system each nutrient is broken down. [10 mins] 4. Students complete worksheet, recapping the organs of the digestive system and their functions. [10 mins] PLENARY 1. Collect results from experiment and explain what it shows. [10 mins]

Assessment Opportunities Listening to and responding to ideas during discussions.

Homework 1. Tell pupils to chew a piece of bread for 5 – 10 minutes. They should then write down what happens and try to explain why. (Bread should taste sweeter as starch is broken down). 2. Write up model intestine experiment.

Notes

‘Food and Digestion’ [LESSON 7] Big Question: What happens to a cheese sandwich when it is eaten?

Science content Explain the journey of a cheese sandwich through the digestive system.

Lesson Objectives Science skills Use key scientific vocabulary in written work.

Transferable skills

Key Words Absorption; Anus; Carbohydrate; Digestion; Dissolve; Enzyme; Fat; Gullet; Hydrochloric Acid; Large Intestine; Liver; Mouth; Protein; Rectum; Small Intestine; Stomach; Teeth Resources: The Journey of a Cheese Sandwich assessed task Secondary resources – textbooks, library books. Lesson Plan STARTER Introduce the task and discuss ideas for how it could be completed. Discuss food groups contained within a cheese sandwich. [5 mins] MAIN Allow pupils to complete the task individually, with access to secondary resources (class notes, text books, library books). [50 mins] PLENARY Discuss progress so far. [5 mins]

Assessment Opportunities Completed tasks should be collected in to be marked according to criteria. Alternatively, students could self-assess or peer-assess according to criteria. Homework Students may need extra time to complete the task at home. Notes This lesson could be completed as an extended homework task.