Food and Digestion

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Food and Digestion

• Year 8 Unit 8a

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Index

• Lesson 1 What's in food?
• Lesson 1a Whats in food? (part 1a with food
  test for starch)
• Lesson 1b Whats in food? (part 1b with food
  test for glusose)
• Lesson 2 Whats in food (part 2 with food tests
  for protein and fat)
• Lesson 3 The digestive process part 1
• Lesson 4 The digestive process part 2
• Lesson 4a Explanations
• Lesson 5 Energy from food
• Lesson 6 Food labels and balanced diets
• Lesson 7 Animal diets
• Lesson 8 Vitamins and minerals
• Lesson 9 Enzymes. Digesting protein in the
  stomach.
• Lesson 10 Catchups.
• Lesson 11 Assessment
• HOMEWORK

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Disclaimer

• This PowerPoint has been composed to support
  science at West Wight Middle School. Teachers
  should consult with the head of dept. before
  undertaking practical work. (There might be
  errors, revisions required or safety updates.)
• Users in other schools do so at their own risk.
  Neither West Wight Middle School or its
  individual staff will be responsible for any
  death, injury, poisoning, misinformation or
  anything even vaguely unpleasant resulting from
  abuse or misuse of this publication.
• Under no circumstances should these tests be
  conducted without qualified adult supervision.

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References

• http//www.ntscience.co.uk/powerpoint/index.html
• http//science-interactive.co.uk/website20content
  2007/pdf20gcse20powerpoint20lessons/Unit2012
  0The20Digestive20System.pdf

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HOMEWORK

• What are the main nutrients (e.g. carbohydrates)
  in food?
• What does diet mean? (Note, its nothing to do
  with losing body mass).
• What uses does the human body make of each of
  these main nutients?
• Copy the nutrient charts from several different
  food packets.
• What vitamins does the human body need?
• What are the main minerals the human body needs?
• What are enzymes and what is their purpose in
  digestion?
• Why do enzymes work best at about 37 degrees C?
• Roughly, what proportions of the main food groups
  are necessary in the human diet?
• In fair testing, what do the following things
  mean?
• Adequate sample size.
• Prediction.
• Control variable.
• Independent variable.
• Dependent variable.
• Fair comparison.
• What is the purpose of the three different types
  of teeth?
• Why is it important that chunks of food are
  broken into smaller pieces?
• Why are complex carbohydrates better long-term
  sources of energy?

• Your teacher may set this as homework through the
  whole unit.
• INSTRUCTIONS
• Copy paste the questions onto your own computer
  or flash drive.
• Work on the questions, one at a time.
• Email your work directly to your teacher or print
  it and pass the print to your teacher.
• RULES
• Write from memory. Read, learn and write. Do not
  work directly from a book or internet text.
• Never cut and paste from the internet. This is
  NOT learning!
• Write answers using full sentences. Most answers
  will require more than one sentence to explain
  clearly.
• If you use tables, diagrams and drawings, write a
  caption to explain what they are about.

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Lesson 1 Whats in food?

• Why do we need to eat anyway?

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(No Transcript)
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Objectives

• Find out what is in food.
• Begin to learn what our body does with it.

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Group learning getting started
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Whats in food?
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Lesson 1a. Food tests (part 1)

• How can we find out if food contains protein,
  fat, starch or glucose?

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Objectives

• How can we find out if food contains protein,
  fat, starch or glucose?
• Learn some new experimental methods.

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Equipment

• For test 1
• Iodine solution in pipette topped bottles (8)
• Spotting tiles (8)
• Sample foods
• For test 2
• Benedicts solution in pipette topped bottles (8)
• 250 cm³ glass beakers (8)
• Test tubes racks (8)
• Glucose powder
• Spatulas (8)
• Eye protection (glasses) (class set)
• Tripods, Bunsens matches.

• For test 3
• Biuret solution in pipette topped bottles (HAZARD
  CORROSIVE)
• Hazcard for biuret solution.
• Protein solution (enough for ½ test tube per
  class)
• Eye protection (glasses) (class set)
• For test 4
• Filter paper (2 or 3 pieces per group)
• Sample foods

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Test 1 Testing for starch

• Use a spotting tile with the food samples.
• Add 2 drops of iodine solution to each food
  sample.
• Which of these foods contain starch?
• Record results.

• For test 1
• Iodine solution in pipette topped bottles (8)
• Spotting tiles (8)
• Sample foods

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WASH YOUR HANDS!
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How should you record?

• This is what one group wrote...
• Method We started by collecting some food for
  our experiment. We put them in a spotting tile
  and dropped a few drops of iodine solution, and
  if it went dark blue/black, it contained some
  starch. But if it went neutral it didn't contain
  starch.

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Heres how it should look...

• Method Food samples were placed on a clean
  spotting tile. Three drops of iodine solution
  were added to each sample. A dark blue/black
  colour indicated that the sample contained some
  starch. Results were as follows...

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Recording homework

• Bookwork

• Bloggers

• Describe the test for starch.
• Include your results.
• Describe how you know if the test is positive.
• Complete as homework.

• Describe the test for starch.
• Include your results.
• Describe how you know if the test is positive.
• What is starch anyway?

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Lesson 1b Testing for glucose

• Food testing

Glucose drinks
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Why are we learning this?

• Glucose is an important source of energy. This
  test shows how we discover is food contains
  glucose.

• How to do a food test for glucose.
• How to deal with potential hazards.
• How to record your findings.

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HAZARDOUS
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Test 2 Testing for glucose

• Use 1 spatula of glucose powder in a third of a
  test tube of water. Dissolve.
• Put in 10 drops of Benedicts solution.
• Heat carefully in a water bath.
• Note your result.

For test 2 Benedicts solution in pipette topped
bottles (8) 250 cm³ glass beakers (8) Test tubes
racks (8) Glucose powder Spatulas (8) Eye
protection (glasses) (class set) Tripods, bunsens
matches.
HAZARD! Use eye protection
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WASH YOUR HANDS!
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Scientific recording

• Describe the test for glucose.
• Explain the hazard and the precautions.
• Draw the method and label.
• Describe how you recognise a positive result.
• Complete as homework.

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Bloggers (please be creative)

• Describe the test for glucose.
• Explain the hazard and the precautions.
• Include a diagram of the method with labels.
• Describe how you recognise a positive result.
• What foods contain glucose?
• What is glucose?
• Complete as homework.

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Lesson 2

• More food tests

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Protein and fat
Can we test for protein and fat?

• Food tests

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Protein This test is a bit more tricky!
Vegetarians may not wish to handle meat products.
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HAZARD! Biuret solution is corrosive. Wear eye
protection throughout the test. Remove only when
all packing away is complete.
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Website to look at...

• http//www.purchon.com/biology/protein.htm

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Test 3 Testing for protein

• Use a pestle mortar to grind up samples of the
  food (separately).
• Put the food sample into a test tube with 10
  drops of Biuret solution.

www.terrible_diagrams.com
HAZARD! Biuret solution is corrosive. Wear eye
protection throughout the test. Remove only when
all packing away is complete.
For test 3 Biuret solution in pipette topped
bottles (HAZARD CORROSIVE) Hazcard for biuret
solution. Protein solution (enough for ½ test
tube per class) Eye protection (glasses) (class
set)
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Positive result?

• If the mixture turns purple, protein is present.
• If the mixture remains a pale blue or pale green
  no protein is present.

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WASH YOUR HANDS!
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Recording

• Describe the protein test using decent sentences
  and diagrams.
• Dont forget the hazard precautions.
• Complete as homework.

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Bloggers

• Add another entry for the protein tests.
• What is protein anyway? Is it in most food?
• Dont forget the risk assessment.

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FAT

• Food tests

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Video input
Keeping a sensitive and balanced view.

• Teachers resources
• Childhood obesity
• Obesity in Britain
• Our bodies need fat. What do we know about fats
  in our diet? What do we know about balanced
  diet?

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Test 4 Testing for fat

• Rub a small piece of each sample food onto part
  of a filter paper.
• Hold the filter paper up to the light. Is fat
  present?

For test 4 Filter paper (2 or 3 pieces per
group) Sample foods
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Questions

• Answers in sentences please
• What type of food is iodine solution used to
  test, and how can you tell if the test is
  positive?
• In science, what does the word solution mean?
• When rubbing different foods on filter paper, the
  paper sometimes becomes translucent. What does
  this tell you about the food?
• What is the main hazard when using Biuret
  solution and what precaution should you take?
• What is the name of the test that will show if
  prorein is present in a food and how will you be
  able to tell?
• Glucose is a type of sugar. Your body uses
  glucose is a source of what?
• What test would you use for glucose and how would
  you know if the test was positive?

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Homework

• Complete the questions about food testing.

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The digestive process Part 1
How does your gut break up food, absorb the good
bits and get rid of waste?

• Lesson 3

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Equipment

• BBC Science in Action DVD 1

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Objectives

• What actually happens to food as it passes
  through the body?
• How do our bodies get the useful stuff out of the
  food?

http//science-interactive.co.uk/website20content
2007/pdf20gcse20powerpoint20lessons/Unit2012
0The20Digestive20System.pdf
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Process.

• Get the food ready to absorb.
• Absorb the food.
• Get rid of waste.

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Video input 1

• BBC Science in Action DVD 1 Animal nutrition /
  Nutrients from food

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Discussion
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Video input 2

• BBC Science in Action DVD 1 Animal nutrition /
  Digestion

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Consolidate your learning

• Work together on these four sentences.
• The human digestive system is made of cells,
  t________ and organs.
• The parts of the s______ break up, d_____ and
  absorb the n_______, minerals and vitamins that
  you need to g____ and do things.
• The d_______ system is able to breakdown
  proteins, fats and c________.
• They are then a______ into the blood.

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Plenary

• Yucky questions
• What questions do you want to ask about digestion?

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The digestive process Part 2
What happens to your dinner as it passes through
your body?

• Lesson 4

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Equipment

• Large poster paper (A2 if possible.) 10 sheets.
• Felt pens.
• A4 diagrams of the digestive system (laminated or
  in study guide)
• Digestive system CD ROM
• BBC Science in Action DVD 1
• DVD The Human Body

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Objectives

• What happens as food passes through the body?

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Starter

• Video The Human Body. Endoscopic cameras

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Digestive system flow chart
What do you think these parts do? How do they
work?

• Mouth
• Oesophagus
• Stomach
• Liver
• Small Intestine
• Large Intestine
• Rectum
• Anus

Make your own flow chart to show the process.
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The parts of the digestive systemWhat do they
look like?
Use Digestive System CD ROM. Discuss
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Assignment

• Work as a team using a large sheet of paper and
  felt pens.
• Draw a large diagram of the digestive system. Use
  faint pencil first to get the proportions right.
• Annotate.

• Mouth
• Oesophagus
• Stomach
• Liver
• Small Intestine
• Large Intestine
• Rectum
• Anus

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diagram
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Plenary

• Each group represents a part of the digestive
  system.
• Your task is to describe verbally and in yucky
  terms, what your part of the system does.

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Homework

• Check your learning so far and make certain the
  following parts are in your presentations
• Food types and food tests.
• The basic digestion process from mouth to anus.

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Explanations

• Lesson 4a

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What happens in your small intestine?
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Objectives

• Improve the way you use proper sentence structure
  to describe and explain how things work using
  proper technical vocabulary.
• Discover how digested food is absorbed by your
  body.

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• Discussion
• What is the small intestine for?
• Why are there villi on the inner surface of the
  small intestine?

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Assignment part 1

• You have heard a bit about how the small
  intestine works.
• In a group of 4 (ish), compose a paragraph that
  clearly shows your knowledge and understanding.
• Avoid the word it.
• Use proper technical vocabulary.
• Use a variety of sentence openers and connectives.

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Reporting to the class.

• Some groups will read their paragraphs to the
  class.
• Things to listen for (marks out of 5)
• Have they used scientific vocabulary?
• Are their sentences easy to understand?
• Have they used a variety of openers?

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Next stage

• Improve your paragraph. (redraft)
• Produce a page in your exercise book (or blog)
  about the small intestine. Use your improved
  paragraph and diagrams.

RESOURCES There are suitable diagrams in the
students resource area on the school intranet.
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Lesson 5 Energy from food
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• Does food contain much energy?
• How much energy do we use (transfer)?

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Equipment

• For students
• Graph paper
• For teachers demonstration
• Icing sugar
• Tripod, bunsen and shallow burning dish
• Matches
• Eye protection

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In this lesson you will

• See energy released from food.
• Investigate how much energy is used during
  different human activities.
• Produce suitable graphs to make results clear.

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Vocabulary

• Energy transfer You cant use energy, only
  transfer it.
• Kilo calories (kcal) The unit of energy used
  mostly in the USA.
• Kilo joules (kj) The unit of energy used in the
  UK.

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QUESTIONS TO CONSIDER

• You have seen energy released from food when
  sugar burns.
• How do we know that energy was in the sugar?
• Would all foods burn and release energy?
• What foods are likely to release the most energy?

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Energy from food.

• Use the data to find out how much energy is used
  doing different activities.
• Bookwork Produce a clear results table in your
  book.
• Bloggers Produce a clear results table on the
  next slide of your labcast.
• The information is at www.runningtools.com/sportnu
  trition.htm

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Energy from food Units of measurement.

• 1 kilo calorie 4.18400 kilo joules
• So, to change kcal to kjoules, multiply by 4.184.
• Bloggers, change your results table to kj.
• Bookworkers, produce a new table showing the
  results in kilojoules.

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Graphs

• Use the data to produce a suitable graph.

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Plenary

• Use mini whiteboards (one each).
• Note one thing you learnt today.
• Note one thing that surprised you.
• Note why energy is not actually used up.

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Lesson 6 Food labels and balanced diets
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Equipment

• Food labels showing nutrition information.

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In this lesson you will

• Use food labels to investigate whats in food.
• Discuss what food labels mean.
• Maybe produce graphs to make results clear.

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Input / Starter

• Video Wan2Tlk Science / balanced diet
• Class discussion

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Remember this?
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Now try this...
Use the food packet labels to make a table like
this.
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Discussion / Plenary

• Mini whiteboards.
• How can you be sure you have a fair comparison?
• Which foods on your list are likely to be the
  most healthy? How do you know?
• Which foods on your list are likely to be high in
  energy? How can you tell?

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Graph

• If theres time or as homework...
• Produce one of the two graphs
• A graph to show the proportion of carbohydrate,
  protein and fat in each food. (Fair comparison
  please!)
• A graph to compare the energy content of each
  food. (Fair comparison please!)

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Lesson 7 Animal diets

• Bored of wildebeest?

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In this lesson you will

• Discover why different animals have different
  diets.
• Discover the importance of carbohydrates,
  proteins and fats in animal diets.
• Learn what sorts of food contains mostly protein,
  mostly carbohydrate, etc.

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Lesson 8 Vitamins and minerals
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In this lesson you will

• Discover what vitamins and minerals the human
  body needs and find out about the effects of not
  having them.

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Lesson 9 Enzymes. Digesting protein in the
stomach.
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In this lesson you will

• Investigate the effects of enzymes on digestion.
• Learn about what enzymes are and what they do.

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Lesson 10 Catchups.
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In this lesson you will

• Have an opportunity to catch up with your
  presentations, reports and results.

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Lesson 11 Assessment