Lesson 1

Unit Title: FOOD AND DIGESTION
Caretaker: JES

Unit No   
 8A

Lesson Title: ON A DIET

NC Ref: 
 Sc2 2,a,b,c,d,j,l

Objectives:    

MK - what the word diet means, what the components of a balanced diet are, what the major components are used for. Key words: balanced diet, carbohydrate, starch, sugar, fat, protein, vitamin, mineral, fibre, nutrition information.
SK - how to compare the content of food using nutrition information panels, problems caused by not getting a balanced diet
CK - examples of diseases caused by deficiencies and ways in which sufferers have to watch what they eat.

Lesson outline: 

Discuss what a diet and balanced diet are, find out which foods are good sources of each food group, Find out why you need each food group.

Starter activities: In groups pupils sort the food group cards into 7 logical groups. You then elicit reasons for the groupings and come up with a list of the 7 food groups. Come up with the definition of a diet ('what you eat') and a balanced diet (eating food from each food group every day in appropriate amounts). Could look at the food pyramid on 8Ab/6 to emphasise this. Record key points as the board as they arise, some of the important ones are in the table below.

Discuss can of 'dog food' (previously made from mars bar and jelly put in a very clean dog food tin). Eat the 'dog food'. Discuss this as a balanced diet for the dog, providing them with all the nutrients they require.

Some background info for this lesson: 

Main course:

Look at 8Aa/4 and discuss the information on Bloggs Crunchy Bar. Ask why there is info for 'per 100g'.
 Pupils look at a wide range of nutritional information panels and find answers to questions such as 'which food contains the highest amount of fat?', Encourage pupils to frame their own questions. 

Then...

Each group could write a single page summary of one or a couple of food groups which includes foods that contain a good source of it, what it is needed for in the body and what might happen if you have an excess  or deficiency of it. The pages could then be brought together into a booklet designed to be left out in a doctors surgery. Encourage pupils to use info on pages 7 and 8 of Exp. Sci. 8 as well as pages 8 and 9 of Key Stage Success (revision guide).

Alternatively....

Pupils make a 'food wheel' (8Ab/3) which has to include the food group, its uses and sources.

Plenary: 8A Food and Digestion Boardworks - slides 3,4 and 5. (pop quiz)

Discuss or give as a home work, what one food type should you eat more of (fibre) and what three food types you should eat less of (salt, sugar and fat).

Timings:

15

15

20

5

Homework Suggestion: 
 Give pupils a paper plate. They must draw or somehow create a balanced meal on it. They must say what each component of the meal is contributing nutritionally.

The more able could do sheet 8Aa/6 or 8Ab/6 or 8Ab /7.

Resources: 

Dog food tin filled with jelly and chopped up mars bars.

Food Group Cards

Nutrition Panels

Exp. Sci. 8 

KS 3 Success (revision guides)

Scissors
split pins
colours
paper plates

8Ab/3    8Ab/6    8Aa/4
8Aa/6 or 8Ab/6 or 8Ab /7.

Lesson 2 

Unit Title: FOOD AND DIGESTION
Caretaker: JES

Unit No   
 8A

Lesson Title: FOOD TESTS

NC Ref: Sc2 2,a,b,c,d,j,l

Objectives:    

MK - the tests for starch, fat, protein, glucose
SK - know why food tests are important
CK - know who would use the tests in industry

Lesson outline: Carry out food tests for each food type and understand why one would need to do this.

Starter activity:

8Aa/3 - true or false activity.
 
Main course:

Discuss carbohydrates as both starch and sugar/ glucose. Could show the diagram on 8Aa/2.

Pupils collect equipment used to test for starch - each group has sample of labelled starch solution, spotting tile with food samples such as crisps and cream crackers - and a food which doesn't contain starch. Instruct pupils to add a drop of iodine to an empty spot and record colour  (brown) then add a drop of iodine to first the starch solution then the food samples. Pupils record the colour of iodine once applied to starch (blue-black)

Pupils rub an oily / fatty food on to filter paper  to test for fat and do the same with a food which is not fatty. Leave to dry. Pupils should observe and record the greasy mark that shows fat to be present.

Pupils add drops of sodium hydroxide and then drops of dilute copper sulphate to a sample of albumin as the test for protein. Pupils observe and record the positive test for protein as purple. (if Biuret solution is provided simply add a few drops of it to the albumin and observe the positive result of purple).

Pupils watch demo or carry out the test for glucose - add Benedicts solution to glucose sample and other samples if time, heat in water bath observe and record colour changes - positive result is brick-red.

Plenary:
 Tidy away! 

Pupils could list foods they expect to test positive for each of the above tests.

Timings:

10

40

10

Homework Suggestion: 
 Find out what 'RDA' means.

Find out about a diet related disease such as kwashiorkor, anorexia, coeliac disease, diabetes.

Resources: 
 spotting tiles                           

test tubes and test tube racks

olive oil and filter paper

selection of food samples

starch solution and iodine solution 

albumin solution and biuret solution (or sodium hydroxide and copper sulphate solutions)

glucose solution and Benedicts solution

8Aa/2.

Goggles must be worn when using Benedicts

Sodium hydroxide is corrosive.

Do not ingest copper sulphate

Lesson 3

Unit Title: FOOD AND DIGESTION
Caretaker: JES

Unit No   
 8A

Lesson Title: YOU'VE GOT GUTS

NC Ref: 
 Sc2 2,a,b,c,d,j,l

Objectives:    

MK - Breaking down food is called digestion, positions and names of organs in the digestive system. Key words: digestion, digestive juice, gut, stomach, mouth, gullet, small intestine, large intestine, rectum, anus.
SK - digestion turns insoluble food molecules into soluble molecules. Meanings of the words ingestion, egestion, saliva, faeces, contract.
CK - about the words peristalsis (muscular contractions of the gut), salivary glands.

Lesson outline: Discuss what digestion is and briefly why it has to happen. Be able to label the digestive system and know what happens where. 

Starter activity:

Pupils will have met the names of some parts of the digestive system in Key Stage 2, although they will not specifically have studied digestion. You could start by asking pupils what they think happens to their food when they have eaten it, and explain that it passes through a long tube in their body called the gut. Record key words on the board. show the knitted gut. Yourself and pupils name the parts. Show rat gut if one is available.

Pupils then write a list of the digestive organs in the order that food moves through them.

 
Main course:

Show the 8A Food and digestion power point - slides 9 to 13. 

Demonstrate peristalsis with a sock and an orange (or something similar).

Discuss that faeces are always brown because of a mixture of bili rubin (from the break down of old red blood cells) and bili verdin (from the break down of bile).

Discuss that sausages used to be made of intestines (lambs for small links and pigs for big links. what do they think cumberland sausages were made from?!). Also that haggis traditionally is made from a sheep's stomach.

Pupils complete 8Ad/4 or label a different digestive system diagram (see biology filing cabinet).

Alternatively,..

 Pupils could make their own poster or group poster. Or provide tubes and string etc. for them to construct a 3-D version of the digestive system.

Plenary: Slide 15 on 8A Food and digestion power point  (digestion quiz) and / or 8Ad/6.

or pupils practice the Digestive System Loop, This may be done for several plenaries with the aim of the class first getting it correct and then to beat the clock.
 

Timings:

15

35

10

Homework Suggestion: 

8Ad/6
Finish digestive system poster.

Resources: 
 Charlottes knitted gut

tubes and things to make 3-D digestive system

Poster materials

scissors

glue

8Ad/4(or digestive system diagram from biology filing cabinet).

8Ad/6 

Lesson 4 

Unit Title: FOOD AND DIGESTION
Caretaker: JES

Unit No   
 8A

Lesson Title: BREAK DOWN

NC Ref: 

Sc2 2,a,b,c,d,j,l
 

Objectives:    

MK - the functions of the stomach and small intestine in digestion, digestion is helped by digestive juices which contain enzymes, enzymes break up large molecules. Key works: Digestive Juice, enzyme.
SK - enzymes work best at certain temperatures and pHs, saliva is a digestive juice, starch is broken down into sugar in digestion. digested food is absorbed by the small intestine. The word absorb.
CK - the liver produces bile which emulsifies fat.

Lesson outline: Enzymes are used to break down large insoluble food molecules, different enzymes work in different conditions and act on different types of food molecule.

Starter activity:

Pupils make up questions to the answers on sheet 8A
 
Main course:

Recall that food has to enter the blood stream at the small intestine in order to be transported round the body.

• Show a meshed bag full of tennis balls- ask how you could get the balls out of the bag without cutting the bag - explain the bag is like the small intestine and the balls like large food molecules. They should work out that they need to be cut into smaller pieces to fit through the holes.

Recall the mention of enzymes in digestive juices last lesson. Show any of the following:

• Cut up a pretend starch molecule in front of the class (could be a paper starch molecule, cut with scissors to represent amylase or could be a string of beads that come apart). Ask them what might represent an enzyme. Explain that starch is large and insoluble and is made of building blocks of glucose, which are small and insoluble and therefore can cross the wall of the small intestine into the bloodstream. Show pages 14-20  of the 8A Food and Digestion PowerPoint . Pupils could draw a series of diagrams to show what is happening. 

• Demo dried peas and sand in a sieve, ask pupils to explain this model.

Pupils make a model gut. Inside visking tubing add methyl blue and potassium permanganate. Explain that Potassium permanganate is dyed starch and methyl blue is dyed glucose, you could add some pretend enzyme too. Place the visking sausage in water. The pupils should draw the diagram and explain what happens and why. Only methyl blue is small enough to diffuse through the small holes of the visking tubing.

Pupils could also or alternatively make the digestion flicker book (8Ad/5).

Plenary: Practice the Digestive System Loop.
 

Timings:

Homework Suggestion: 
Pupils chew on a piece of bread without swallowing and  record the change in taste and explain it.

Pupils eat a large portion of beetroot and observe their faeces.

'Breakdown'
 

Resources: 

Visking tubing, methyl blue and potassium permanganate

Mesh bag of tennis balls

Sieve with dried peas and sand

Digestive system Loop
 

8A

8Ad/5
 

Potassium Permanganate: wash off if get on skin

Lesson 5 

Unit Title: FOOD AND DIGESTION
Caretaker: JES

Unit No   
 

Lesson Title: IN THE BLOOD

NC Ref: 
 Sc2 2,a,b,c,d,j,l

Objectives:    

MK - Digested food is absorbed at the small intestine, digested food dissolves in the blood and is carried around the body, the heart pumps blood through blood vessels
SK - Villi provide a greater surface area for absorption, the wall of the small intestine is very thin so that substances can be absorbed quickly, Digested food passes into capillaries, arteries carry blood away from the heart, veins carry blood to the heart
CK - Cells get food from tissue fluid, what fats are digested into (fatty acids and glycerol), about microvilli.

Lesson outline: Pupils learn how digested food is absorbed through the wall of the small intestine and transported round the body.

Starter activity:

Pupils complete the phrases on sheet 8Ac/3.
 
Main course:

Demo a model small intestine with starch and amylase. Pupils could make their own or take samples from several set up previously. The glucose should diffuse through into the water. The water should be tested for both starch (using iodine) and glucose (using Benedicts). However, this can be quite unreliable and the water will need 'doctoring' with glucose in order to get the desired result.

This shows that small and soluble food molecules can go through the wall of the small intestine and into the blood this is absorption.

Adaptations of the small intestine for absorbing digested food:

Show the knitted gut again (and the rats gut if available) and remind pupils of the length of the small intestine.

Pupils draw circles to represent a cross section of the small intestine, one to show a folded wall and one not. They trace the inner wall circumference with a piece of string and should realise that the folded inner wall requires a longer piece of string to complete. This illustrates the large surface area provided by folds of the inner wall for efficient absorption of digested food into the blood stream.

Show the small intestine model made by CLL, the towel shows the many folds of the inner wall of the small intestine. Explain that the folds are called villi and inside each villus are capillaries carrying blood which collects the digested food and transports it round the body. Pupils complete sheet 8Ae/4.

Show the Circulatory System Animation  to help explain that the heart pumps the blood around the body, delivering the digested and absorbed food to all parts of the body.

Pupils complete the questions on Page 14 and 15 of Exploring Science 8.

Plenary: Pupils practice the Digestive system Loop.

Timings:

10

40

10

Homework Suggestion: KEY HOMEWORK!!!

Use the following key words to describe the story of a potato chip from being on the end of your fork to reaching the cells in your big toe.

saliva / enzyme / sugar or glucose / gullet or oesophagus / stomach / small intestine / absorption / capillary / villus / blood / artery / heart.
 

Resources: 

Visking tubing, starch, amylase, glucose, iodine, Benedicts

Model small intestine

Exploring Science 8
 

8Ae/4.

Lesson 6

Unit Title: FOOD AND DIGESTION
Caretaker: JES

Unit No   
 8A

Lesson Title: FAT DIGESTION & USES OF DIGESTED FOOD

NC Ref: Sc2 2,a,b,c,d,j,l

Objectives:    

MK - fat digestion requires bile (made in the liver) to increase surface area for enzyme action, 
SK - fat is broken down by lipase into fatty acids and glycerol.
CK - digested food is used by cells for respiration and to construct new substances.

Lesson outline: Pupils learn how fat is digested and what digested food is used for.

Starter activity: Pupils answer the questions below in pairs in the back of their books or do the digestion quiz on slide 15 of the Food and Digestion Power Point. (if not done already).

Main course:
 Show the action of bile on fat (add washing up liquid to olive oil in a petri dish and  shake around a little) and project with an over head projector or pass round to show the globules of fat.

Explain that this is called emulsification and that the globules are still fat and are too big to be absorbed into the blood.

Show slide 20 of the Food and Digestion Power Point and explain that bile increases the surface area for the action of the enzyme lipase to break down the fat into fatty acids and glycerol. These molecules are small enough to be absorbed into the blood stream. Pupils copy the information from slide 20.

Pupils copy the diagram on page 15 of Exploring Science 8 to show what happens to digested food when it reaches the body cells.

Plenary: 

emulsification / absorption / eating / digested food used by cells / enzyme action 

Pupils put the words above into the correct order to describe fat digestion and use.
 

Timings:

10

Homework Suggestion: 
 Research the causes, effects and ways to help heart disease.

Resources: 
 Exploring Science 8

Olive oil / petri dish (es) / washing up liquid

Lesson 7 

Unit Title: FOOD AND DIGESTION
Caretaker: JES

Unit No   
 8A

Lesson Title: FOOD AND DIGESTION REVISION

NC Ref: Sc2 2,a,b,c,d,j,l

Objectives:    

MK - All pupils to revise the topic
SK - 
CK - 

Lesson outline: Pupils aim to consolidate their knowledge of food and digestion by doing the following tasks:

Starter activity:

Pupils complete the digestion crossword - 8Ae/3

Main course:

Pupils complete the digestion concept maps - either 8Ae/5 or 8Ae/2,  This could be made into a poster and include illustrations.

Plenary:
 

Pupils explain parts of the concept map to the rest of the class.

Timings:

10 -15

35

10 - 15

Homework Suggestion: 

Revise for test next lesson.
 

Resources: 
 

8Ae/5

8Ae/2.