C3 lesson part one

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C3 lesson part one

  1. 1. C3 Food Matters Route map Over the next 12 lessons you will study : Friday 21 October 2011 C3.1 The food chain C3.2 Farming challenges C3.3 The nitrogen cycle C3.4 Intensive farming End of module test C3.5 Organic farming C3.6 Preserving and processing food C3.7 Chemicals in a healthy diet C3.8 Harmful chemicals in a healthy diet C3.9 Diet and diabetes C3.10 Type 2 diabetes C3.11 Food and the consumer C3.12 Food hazards and risks C3.1 The food chain C3.1 The food chain
  2. 2. C3.1 The food chain Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand how the food industry ensures a constant supply of food products through the human food chain </li></ul><ul><li>Understand the journey from farm to plate of food products </li></ul>We will focus on. Friday 21 October 2011 First activity: Think of a typical food chain and answer the following: a) what is a producer b) what is a consumer c) what information does a food chain show and d) what’s the difference between a food chain and web ? Literacy: Farming, agriculture, crops, harvest, processing, transport, distribution, supermarkets, storage supply chain, food chain, agriculture, Numeracy: Scientists recommend that we eat five portions of fruit and vegetables each day. In some case eating five portions of fruit or vegetables can halve the risk of contracting certain disease including colon cancer PLTS Creative thinkers Reflective learners We will focus on generating and exploring ideas. Team workers Effective participators Self managers Independent enquirers
  3. 3. C3.1 The food chain Decide whether the following statements are true or false: Introduction: A food chain or food web shows how different organisms feed on each other. It can also show the flow of energy or biomass form producer to top consumer In the food industry a food chain refers to the path of how the food has got from the farm or field to your plate. Take a beef burger, which has three main parts, the beef, the salad and the bread role. Getting each part to the consumer requires its production, transport, processing storage and distribution Extension questions: 1: Think of a loaf of bread, explain using a flow chart how from wheat in a field it arrives on your plate as a slice of bread ? 2: Explain why animals like cattle that are used to produce both milk products and beef are so useful to humans ? 3: Explain why eating mange tout grown and shipped form Kenya is not particularly environmentally friendly ? 4: Why is transport of food an important part of the food chain ? 5: What choices do people make when buying and eating food ? Know this: a: Know that the term ‘food chain’ has different meanings in Biology and in the food industry. b: Know that some people want us to eat more food that is grown locally and in season. Friday 21 October 2011
  4. 4. C3.1 a Look at the photograph and information and answer all the questions: Currently around 60% of land in the UK is used by farmers meaning that it is used to grow crops that go directly into the human food chain or indirectly as animal feed used by framers to provide high quality animal protein. In this country, we only make enough food to feed this country for about 80 days of any year. The rest is flown or shipped in from other countries. Explain the journey from farm to plate for a) corn b) pasta and c) lamb meat ? Give one advantage ad one disadvantage of using modern farming techniques like those pictured above left ? Give the role of a) farmers b) food manufactures and c) the supermarket in the human food chain Key concepts
  5. 5. C3.1 b Look at the photograph and information and answer all the questions: Food chains shows us how energy in food molecules move through from producers to top predators. The food chain opposite shows how cows can convert the nutrients in grass into high quality protein. Using an pyramid of energy also shows us how much energy is lost between each feeding level. Energy is lost because of respiration, body heat and waste. Explain why cattle are used to turn indigestible plant crops like grass into high quality animal protein ? Less than 1600 kJ of the 40,000 kJ of energy contained in grass enters the human food chain as beef. Explain why this value is so low ? Explain how micronutrients move from plants into herbivores and beyond into the human food chain ? energy energy 200,000 kJ 40,000 kJ 3200 kJ 1600 kJ respiration waste respiration waste body heat energy waste indigestible Flow of energy (kJ) Key concepts Sun Grass Cow Beef (human)
  6. 6. C3.1 c Look at the photograph and information and answer all the questions: Wheat is an ideal crop because it is a rich source of carbohydrates. The glucose made during the growing season is converted into starch and stored in the wheat kernels. These are ground into flour and then widely used to make bread, pastries, pasta and cakes. Wheat is also used as an animal feed during the production of meat. Name the three elements that carbohydrates are made from ? Name three other crops that are important for supplying carbohydrates to the human food chain ? We use proteins for growth and repair, fats for long term energy and insulation...what does the body use carbohydrates for ? Key concepts
  7. 7. C3.1 Plenary Lesson summary: chain plate events links Friday 21 October 2011 Buying food in season form local sources is becoming increasingly poplar as the UK population are beginning to realise that flying and shipping in fruit, meat and vegetables form the four corners of the plant is environmentally unacceptable How Science Works: Research nutrient recycling in soils used to grow crops like wheat and corn and the control of pest and other factors which can reduce crop yield Preparing for the next lesson: Bread, cakes, biscuits and pasta are at the end of a long trail of ______ that start on the farm. This is called the food _______ in industry. This chain ______ farms to your ______ of food. Decide whether the following statements are true or false : False True 3: In industry the term ‘food chain’ tells us what eats what ? False True 2: A fertile soil doesn’t contain all the nutrients for healthy plant growth ? False True 1: Flour is made by grinding flowers ?
  8. 8. C3.2 Farming challenges Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand the methods used to keep soils fertile </li></ul><ul><li>Understand ways of protecting crops from pests </li></ul><ul><li>Understand how elements are recycled in the environment </li></ul>We will focus on. Friday 21 October 2011 First activity: Over time repeated use of the same soil can diminish its quality and reduce its essential nutrients. What impact would this have on crop growth and yield and how do pests and other factors like weed growth reduce the crop yield. Literacy: Crops, soil quality, yield, carbohydrate, protein, pest, pesticides, insecticides, fungicides, herbicides and fertilisers . Numeracy: In the UK the control of pest and other factors that reduce the overall yield of crops cost farmers many millions of pounds each year. PLTS We will focus on being creative thinkers and effective participators. Independent enquirers Creative thinkers Reflective learners Team workers Effective participators Self managers
  9. 9. C3.2 Friday 21 October 2011 Extension questions: 1: Where does the carbon in plant carbohydrates come from and write out the word equation for photosynthesis ? 2: Explain what will happen if farmers continually use the same field to grow their crops 3: What main elements do proteins contain ? 4: Why do farmers use fertilizer on their soils ? 5: Explain why it is important for the farmer to control pests on their farms ? Know this: a: Know that fertile soil produce healthy high yield crops. b: Know that essential minerals and elements are recycled over time c: Know that plants make carbohydrates and proteins from glucose Introduction: Farmers must ensure that their crops are healthy and their yields are high, otherwise they will not be able to profit when their crops are sold. They need to make sure the soil is fertile and that their crops are not short of water. They must also protect their crops from pests such as weeds, insects and diseases using pesticides. Some pesticides are natural chemicals, whilst others are manufactured. Plants convert glucose (from photosynthesis) into carbohydrates and they make proteins using nitrogen from the soil. Other essential minerals such as phosphorous and potassium are also gained from the soil. These help plants to grow healthier roots and make flowers, fruits and seeds respectively. Farming challenges
  10. 10. C3.2 a Look at the photograph and information and answer all the questions: Cycling of many plant nutrients, especially nitrates, potassium and phosphates follows the cycling of decaying organic matter form the bodies of dead animals and plants. This organic matter becomes food for decomposers. As organic matter is broken down to simpler compounds, plant nutrients are released in available forms for root uptake and the cycle begins again. Give three types of microbes that can acts a decomposers ? Explain why farmers usually only use a field for 2 years on one year off when growing crops like corn, wheat and potatoes ? Explain why animal waste or manure is spread back onto field just prior to planting in the spring ? Recycling of micronutrients dead organic matter soil nutrients Potassium Phosphates Nitrates decomposers Soil nutrients Plant growth Plant or animal biomass Plant or animal death Magnesium Key concepts
  11. 11. C3.2 b Look at the photograph and information and answer all the questions: Soil in most parts of the World is only around one to two metres thick above bedrock and yet this layer supplies the minerals and water plant life requires to grow. Soil contains weathered rock particles, dead plant material, water and even some living material. The quality of soil can decrease over time if crops are continually grown on it List three things soil provides all growing plants ? Compare the typical soil of this country to the soil found in an dry region like North Africa ? You suspect that your soil has low levels of nitrates and this is affecting your crop yield. How could you improve the quality of your soil ? Crop Humus Fine sediments Course sediments Bedrock Structure of soil Key concepts
  12. 12. Key concepts Look at the photograph and information and answer all the questions: Explain why over use of insecticide may affect the quality of your soil for the next crop ? C3.2 c Cycles of soil nutrients Soil fertility refers to the amount of nutrients in the soil, which is sufficient to support plant life. To be fertile, soil needs macronutrients, which include nitrogen, potassium and phosphorous; micronutrients, which include sullphur, chlorine, copper, manganese, molybdenum, boron, iron, cobalt, magnesium, zinc and chlorine. It must contain organic matter and a relatively low pH value. The soil must be well drained Explain why crops grow less well if there have to compete with weeds for their micronutrients ? soil nutrients decomposers Potassium Phosphates Nitrates
  13. 13. C3.2 Plenary Lesson summary: fungus nutrient infection potassium Friday 21 October 2011 Easter island was first colonised in 300 AD, but by the time Cook discovered it in 1776, he found a few inhabitants near to starvation. What had gone wrong was simple. The island was originally covered with trees and a rich top soil. To grow more food they cleared the trees which worked for a while. Strong winds, rain and over use reduced the quality of soil to a point where no food was grown. How Science Works: Research the nitrogen cycle and the importance of soil nitrates for healthy plant growth. Preparing for the next lesson: Each crop has its own ________ needs. Fertilizer may contain one or more of the elements nitrogen (N), phosphorous (P) and _________ (K). _________ by a fungus can do a great deal of damage to a wheat crop. The ______ quickly spreads once the plant is infected. Decide whether the following statements are true or false : False True 3: The yield of a crop tells us how much was harvested ? False True 2: Pesticides called herbicides kill insects ? False True 1: Nitrogen compounds are taken in by the leaves of a plant ?
  14. 14. C3.3 The nitrogen cycle Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand the role of nitrogen plays in healthy crop growth </li></ul><ul><li>Understand that nitrogen in the form of nitrates is recycled when material form rotting plants and animals is decomposed by microbes including bacteria and fungi </li></ul>We will focus on. Friday 21 October 2011 First activity: Think of a field containing top soil rich in nutrients. This field is either used to grow crops or grass to fee animals. How does the soil lose nutrients and gain nutrients. PLTS Independent enquirers Creative thinkers Reflective learners We will focus on creative thinking and exploring possibilities Team workers Effective participators Self managers Literacy: Nitrogen cycle, nitrates, nitrogen, decomposers decay, ammonium compounds, microbes, fungi, bacteria and soil fertility. Numeracy: Ammonia is manufactured before fertilizers containing nitrates can be produced. The annual production worldwide of ammonia is 130 million tonnes, most of which is used by farmers to improve the quality of their soil.
  15. 15. C3.3 Extension questions: 1: Explain why crop yields will fall if essential minerals like nitrates are not replaced by using animal manure or fertilisers ? 2: If an animal dies explain how the nitrogen that is contained in its body is recycled into the soil ? 3: What elements do proteins contain and how are they different from carbohydrates ? 4: If plants can’t use nitrogen in the form of N 2 , how do they get their nitrogen ? 5: List four ways in which nitrogen is added to the soil naturally. Know this: a: Know that natural and human activities contribute to the nitrogen cycle in the environment. b: Know that plants cannot use nitrogen in the form of N 2 , but can use nitrogen in nitrate compounds and ammonium compounds. Friday 21 October 2011 Introduction: Nitrogen, along with carbon, hydrogen and oxygen is vital for life. This is because there are important nitrogen compounds in living things. The genetic code is written in DNA molecules, which contain nitrogen. Enzymes that control all living processes and other proteins are made using nitrogen. Plants take in nitrogen in the form of nitrates and other minerals form the soil use the nitrogen to make protein. Animals obtain their essential nitrogen by eating plant or animal matter. The nitrogen cycle
  16. 16. Key concepts Look at the photograph and information and answer all the questions: C3.3 a Explain how a) nitrogen moves form soil to plants b) from plants to animals c) from animals back to the soil and d) from the air to the soil ? Although nitrogen is found proportion of the air, it is often a limiting factor for plant growth.  This is because plants can absorb nitrogen only in the form of nitrate (NO 3 - ) Because of this, nitrogen - in the form of nitrate - makes up a large proportion of most commercial fertilisers. Unfortunately, excessive amounts of nitrate in agricultural run-off can have harmful effects Plants Nitrates NO 3 - Ammonium NH 4 + Atmospheric N 2 Nitrifying bacteria denitrifying bacteria Nitrifying bacteria Nitrifying soil bacteria Nitrifying fixing root nodules Decomposers Plant assimilation
  17. 17. Look at the photograph and information and answer all the questions: There’s an old wives tale that states that cemetery soil is very nutrient rich...could this be true and why ? How are nutrients recycled in marine environments (oceans and seas) ? C3.3 b Recycling by invertebrates Decomposers Many small insects, arthropods and microbes are important first and second stage shredders and decomposers of plant and animal remains. In soils where such decomposers are excluded by intensive cultivation or excess chemicals, the natural recycling of organic matter is slowed down. This can lead to decreased soil fertility and plant growth; farmers or gardeners are then forced to add fertilizers. Explain what happens to the organs and tissue of a dead animal in the days following its death and how are minerals locked in its body important for soil quality? Key concepts
  18. 18. Key concepts Look at the photograph and information and answer all the questions: C3.3 c Soil minerals and healthy plant growth Normal growth No phosphates No nitrogen No potassium Intensive farming year after year, reduces the quality of the soil, stripping all the essential plant minerals like nitrates, phosphates and potassium. Farmers add fertilisers at the beginning of every growing season to replace these lost minerals. Crop yield in intensive farming depends on the amount of fertilisers added to the soil. A farmer suspects that his fields have poor soil after several years of very low crop yields.... What should he do to restore his crop yields ? Other than fertiliser, what else could the farmer add to his soil to improve the levels of minerals in the soil ? Normal growth: Corn is an rich source of carbohydrates in the human diet. Lack of Phosphates: Poor growth rates, poor root growth and purple younger leaves. Lack of Nitrogen: Stunted growth, low protein content and yellow older leaves. Lack of Potassium: Poor growth rates, yellow leaves with dead spots.
  19. 19. C3.3 Plenary Lesson summary: microbes continual decompose nitrogen Friday 21 October 2011 Organic farming does not allow farmers to use fertiliser to improve the quality of their soils over time. Organic farmers must use animal manures as a natural alternative. These animals must also be organic and free form chemicals including antibiotics. How Science Works: Research into intensive farming and how these methods have a) improve food supply to humans as consumers and b) reduced the cost of food in real terms over the last 100 years Preparing for the next lesson: There is a ________ cycling of nitrogen on Earth. Plants take in nitrogen from the roots and animals through feeding. _________ is returned to the environment when animals excrete or when animals and plants die and _________. The process of decay is carried out by _________. Decide whether the following statements are true or false : False True 3: The formula of ammonia is NH 4 ? False True 2: Ammonia is produced from nitrates ? False True 1: Plants take in nitrogen from the air through their leaves ?
  20. 20. C3.4 Intensive farming Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand what intensive farming is </li></ul><ul><li>Understand that there are advantages and disadvantages of intensive farming </li></ul><ul><li>Understand how organic food is produced </li></ul>We will focus on. Friday 21 October 2011 First activity: Chicken is produced in this country largely by intensive ‘so called’ battery farms. In your opinion are they ethically run or should all chicken be free range and organic ? PLTS Independent enquirers Creative thinkers Reflective learners We will focus on taking responsibility, showing confidence in ourselves and our. Team workers Effective participators Self managers Literacy: Intensive farming, agriculture, farming, fertiliser, pesticides, herbicides, crop technology, organic farming and yield. Numeracy: Nearly 40% of all lorries on our roads carry food form field to plate. Approximately 12% of all the fuel used in the UK is for food transport. Crude oil is also used a a raw material when making plastics for food packaging.
  21. 21. C3.4 Intensive farming Extension questions: 1: Explain why intensive farming is essential if farmers are to successful produce sufficient food for 6 billion people ? 2: Explain why intensive farming wouldn't be possible without a) crude oil b) pesticides or herbicides and c) farm machinery ? 3: Explain what damage can be done to organisms living in rivers and lakes due to the over use of fertilizers on nearby farmland. 4: How do intensive farming methods keep the cost of food down ? 5: Why do we import a lot of our fruits and vegetables into the UK? Know this: a: Know that intensive farmers aim for as large a yield as possible. b: Know that farmers can use intensive methods while still being committed to the environment, for example by controlling their use of fertilizer. Friday 21 October 2011 Introduction: Milk, animal meat, eggs and most fruit and vegetables are produced using intensive farming methods. Intensive farmers aim for as large a yield as possible at the lowest possible cost. The quality of products coming form intensive farming is not their main concern, yield and profit are. Their fields are so large they need machinery to work on them. Intensive farming gives rise to cheaper and more abundant foods and in a consumer driven society such as ours, some believe this to be a benefit. However, environmental effects also need to be considered, for example the over use of synthesised fertilizers.
  22. 22. Look at the photograph and information and answer all the questions: Food chains shows us what eats what in a particular habitat. They show the flow of nutrients or food energy from producers through primary and secondary consumers. As humans we are all part of a very complex food web. The food chain opposite shows how the cow can convert the nutrients in grass into very high quality protein and fat. Explain why livestock like cows, sheep, pigs and chicken are very important to humans and the human food chain ? Less than 15% of the energy contained in grass enters the human food chain as beef. Explain why this value is so low ? List three other crops that are used to feed livestock like cows, pigs and chicken ? Grass Cow Human (Beef) C3.4 a Key concepts
  23. 23. C3.4 b Look at the photograph and information and answer all the questions: What is the real cost of all the food we produce and sell but do we know the real cost ? To grow crops to feed us or livestock like cows we need land that is cleared. Both fertiliser and pesticides are used to help the crops grow. We use large amounts of crude oil to make fertilisers and transport the food. We also use lots of water to wash the produce and before it is sold. Describe the differences between the living conditions of battery chicken to a free range chicken ? Battery reared chicken meat now costs about £8.00 per kg. If we all went ‘free range’ that price would rise to about £13.00 per kg...explain why some people do not want to pay the additional cost ? Recently sales of expensive organic chicken free from fertilisers and antibiotics have fallen during the recession...explain why? Land Pesticides Water Transport Waste Fertilisers Herbicides Packaging Storage Cost of food Key concepts
  24. 24. C3.4 c Look at the photograph and information and answer all the questions: We eat lots of animal protein like chicken. Chicken are fed corn. Animals are very inefficient at taking plant biomass and turning it into protein that we can eat. Think of a chicken, it consumes over its 9 month life 80 times its own mass of corn. Most of the food energy in the corn is used for respiration and body heat. Also, only a small fraction of the carcass is edible flesh. Explain why livestock like cows, sheep, pigs and chicken are very important to humans and the human food chain ? Look at the diagram left, explain why we would consume less food resources if we all gave up meat and ate only plant material like soya, rice, wheat, potatoes and corn ? Explain why it takes a lot more arable land to feed meat eaters when compared to vegetarians ? Sun Corn Chicken Sun Corn Human (meat eaters) Human (vegetarians) Key concepts
  25. 25. C3.4 Plenary Lesson summary: yield ethical practices welfare Friday 21 October 2011 Over half the energy (supplied largely form fossil fuels) used in agriculture is used to make fertilisers. Intensive farming which uses high amounts of fertiliser and large machines relies on cheap crude oil. When these fossil fuels run out in the next 50 to 80 years, we may face a food shortage here in the UK and across the planet. How Science Works: Research the differences between intensive and organic farming. Preparing for the next lesson: Intensive farming has its advantages and disadvantages. Many animal ________ groups petition against intensive farming because they believe _________ are not ________. The whole point of intensive farming is as large a _____ as possible. Decide whether the following statements are true or false : False True 3: Manure leaking into streams is good for the water and habitats of fish ? False True 2: Traces of pesticides may remain in food products when sold ? False True 1: Weeds compete with crops for space, light, water and nutrients ?
  26. 26. C3.5 Organic farming Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand how organic farming differ to intensive farming </li></ul><ul><li>Understand the advantages and disadvantages of organic farming </li></ul><ul><li>Understand the practise of ‘sustainable development’ </li></ul>We will focus on. Friday 21 October 2011 First activity: Explain why families want to buy organic foods despite the additional cost and why do you think UK supermarkets import well over half of the organic food eaten in the UK ? PLTS Independent enquirers Creative thinkers Reflective learners We will focus on creative thinking and reflective learning. Team workers Effective participators Self managers Literacy: Organic farming, organic products, animal manure, crop rotation, set aside, natural predators and sustainable development. Numeracy: Well over half the organic food eaten in the UK is imported. A basket containing 26 items of organic food had travelled a total distance by all the products equivalent to six times around the equator.
  27. 27. C3.5 Extension questions: 1: Explain why organic farmers are not allowed to use a) fertilisers and b) pesticides or herbicides ? 2: Explain why organic farming methods yields less produce therefore raising the prices of organic foods at the supermarket ? 3: Explain the term crop rotation and what is the purpose of the Soil Association ? 4: What is the purpose of the a) The Soil Association ? 5: Explain why organic farming doesn’t cut down on the distance that food travels from the farm to your plate. Know this: a: Know that organic farming methods avoid using fertilisers, pesticides and other toxic chemicals. b: Know that organic farms use animal manures and crop rotation to keep the soil fertile. Friday 21 October 2011 Introduction: Many organic farmers keep animals and grow crops. They use manures instead of fertilizers and rotate their crops, and use natural predators to control pests, eg. ladybirds that feed on greenfly. The Food Standards Agency says there is not sufficient evidence that organic food is healthier than intensively farmed food, although consumers do say it tastes better. Organic farming is sustainable in that nutrients are recycled and less waste produced. However the distance travelled from farm to our plates can still be vast. Organic farming
  28. 28. Key concepts Look at the photograph and information and answer all the questions: Explain why the use of chemical fertilisers or pesticides is banned when farmers what to describe their crops as being ‘organic’ C3.5 a Organic farming Organic farming is the form of agriculture that relies on techniques such as crop rotation, green manure, compost and biological pest control to maintain soil productivity and control pests on a farm. Organic farming excludes or strictly limits the use of manufactured fertilizers and pesticides, livestock antibiotics, food additives, and genetically modified organisms. Explain why planting crops like peas in the UK and peanuts in the USA increase the yield of crops grown on the same soil the following year ? Organic wheat Three years of grass Two years of cereal crop Natural predators Animal manure
  29. 29. C3.5 b Look at the photograph and information and answer all the questions: We all enjoy good quality food at affordable prices here in England. Intensive farming methods, modern breeds of livestock and varieties of crops help keep the cost of food produced to a minimum. Ethically sourced and produced food is more expensive, however ‘organic’ or ‘fair-trade’ products are becoming more popular and now account for 8%of the total food market. Fair trade products aim to give the grower a ‘fair price’ for their crops as well as help invest in the local community...explain why this is a more ethical way of farming ? Describe the differences between the growing conditions for intensively farmed crops when compared to crops grown using organic methods ? Intensively farmed crops are grown using pesticides and herbicides. These chemicals bio-accumulate and can affect our health...should we continue to use them ? Key concepts
  30. 30. C3.5 c Look at the photograph and information and answer all the questions: Organic farmers will use manual weeding instead of herbicides and natural predators instead of chemicals. Ladybirds trap, kill and feed on their prey the aphid. Aphids can feed of crops causing damage to the stem and reducing crop yield. This will reduce the profit for the farmer and increase the cost of our food at the supermarket. Explain why organic farmers cannot use chemicals like herbicides and pesticides ? Look at the graph above left, explain why cold winters reduce a) the number of aphids and b) the number of ladybirds ? Think of other pests and how they could be controlled using natural predators ? Key concepts
  31. 31. C3.5 Plenary Lesson summary: control rotation expensive natural Friday 21 October 2011 How Science Works: Research the ways in which the food industry use to make our food more appealing? Preparing for the next lesson: Organic farmers use crop _______ and manures to keep their soil fertile. They also use natural predators to control pests. This is called biological _______ of pests. Some people believe organic farming is better for the environment because it keeps _____ habitats in tact. Organic food is more ________ than intensively farmed food. Organic foods are free form pesticides and herbicides are claimed to be better for your health. Farmers who work and use these toxic chemicals would show high rates of cancer or a lower than average life expectancy, not so farmers actually live slightly longer than average Decide whether the following statements are true or false : False True 3: Organic farming is 100% sustainable ? False True 2: The Soil Association is one agency that sets standards for organic producers ? False True 1: Using natural predators to control pests is an example of biological control ?
  32. 32. C3.6 Preserving and preserving food Decide whether the following statements are true or false: <ul><li>Lesson objectives: </li></ul><ul><li>Understand what food additives are and why they are added to food </li></ul><ul><li>Understand that food additives can improve foods </li></ul><ul><li>Understand that some food additives have been linked to health effects </li></ul>We will focus on. Friday 21 October 2011 First activity: List the three things that you believe are added to our food. Also some colours used in children’s sweets have been linked to causing hyperactivity. Do you think the government should do a study and if found to change children’s behaviour ban their use ? PLTS Independent enquirers Creative thinkers Reflective learners We will focus on independent enquiry and creative thinking. Team workers Effective participators Self managers Literacy: Food manufacture, food additives, preservatives, antioxidants, dyes, emulsifier, stabilizes and E-numbers Numeracy: There are approximately 1000 E-numbers that are legally allowed to be added to our foods. Each E-number is a chemical and each has its own purpose.
  33. 33. C3.6 Extension questions: 1: Explain why the following food additives are used a) antioxidants b) food dyes c) food flavouring and d) food stabilisers ? 2: Why do food manufacturers want to make products more appealing particularly those marketed at children ? 3: In the olden days how did people preserve their food ? 4: Explain why food additives have to been shown as an ingredient on a products food label ? 5: E300 is vitamin C, is this a natural or artificial food additive ? Know this: a: Know that preservatives are added to food to keep them from going off. b: Know that additives are added to food to make them more appealing to the eye and our taste buds. Friday 21 October 2011 Introduction: Food can go off. This is caused by chemical changes and changes caused by micro-organisms. To prevent this antioxidants are added to food. Food manufacturers use food additives to create products that we will want to buy and eat. Colour and flavour is enhanced to make food more appealing. Emulsifiers and stabilizers are added to give food a nice texture and to stop ingredients from separating. An E-number tells us that a food additive has passed safety tests and is allowed to be used in the European Union. Preserving and processing food
  34. 34. C3.6 a Look at the photograph and information and answer all the questions: Processed foods like hot dogs contains lots of different food additives including preservatives, dyes, stabilisers, flavourings. Some of these additives have been shown to cause health effects in other animals including cancer. The average hotdog has around 7 different artificial additives. Over 7 billion hot dogs are sold in the USA every year ! Hotdogs contain mechanically recovered meat. This ‘meat’ is obtained by smashing the bones of an animal against a metal grid. Do you think it should be still called meat ? Hotdogs are rich in vitamin C. Is this a good source of an essential vitamin in your diet ? soy protein wheat gluten sorbital sodium lactate sodium diacetate sodium phosphate sodium erythorbate sodium nitrite sodium nitrate ascorbic acid flavour enhancer flavour enhancer artificial sweetener preservative flavour preservative preservative preservative preservative preservative, vitamin c Food additives in the humble hotdog Hotdogs once buried take a long time to decompose. Explain one reason why ? Additive Role Key concepts
  35. 35. Key concepts Look at the photograph and information and answer all the questions: C3.6 b Using anti oxidants Apples and other produce when cut can go brown as oxygen reacts with chemicals inside the apple flesh. The browning and spoiling of the fruit can be slowed or prevented by inactivating the enzyme with heat (cooking), reducing the pH on the surface of the fruit (by adding lemon juice), reducing the amount of available oxygen (by putting cut fruit under water or vacuum packing it), or by adding certain preservative chemicals (like sulfur dioxide). Give three ways in which you can stop freshly cut fruit like an apple from browning in air containing oxygen ? Give an example of a food that is preserves using a) vacuum packing b0 canning and c) freeze drying ?
  36. 36. Key concepts Look at the photograph and information and answer all the questions: C3.6 c E numbers found in foods E numbers are number codes for food additives. They are commonly found in many processed foods across Europe. Some food additives are natural for example E300 is vitamin C and some are artificial. With the hundreds of E numbers used to colour, preserve, stabilise, thicken, emulsify, prevent oxidation, regulate pH and flavour our modern foods would be much more expensive to produce. <ul><ul><li>E100–E199 (colours) </li></ul></ul><ul><ul><li>E200–E299 (preservatives) </li></ul></ul><ul><ul><li>E300–E399 (antioxidants, acidity regulators) </li></ul></ul><ul><ul><li>E400–E499 (thickeners, stabilizers, emulsifiers) </li></ul></ul><ul><ul><li>E500–E599 (acidity regulators, anti-caking agents) </li></ul></ul><ul><ul><li>E600–E699 (flavour enhancers) </li></ul></ul><ul><ul><li>E700–E799 (antibiotics) </li></ul></ul>Give a food that might contain the following a) a colourant b) a anti-oxidant c) a flouring d) an emulsifier and e) a thickener ? Explain why some people may wish not to buy foods containing E numbers particularly colours and flavourings found in children's sweets ?
  37. 37. C3.6 Plenary Lesson summary: illegal consumers law processing Friday 21 October 2011 Without food additives processed food would have a shorter shelf life and cost the consumer far more. Highly processed foods would also look and taste less appealing. Although food additives support the journey from farm to plate there are some that are known to have certain health risks including causing cancer and hyperactivity in children How Science Works: Research into the chemicals needed for a healthy diet in humans Preparing for the next lesson: Food labels are used to tell _________ what has been added to our food during __________. Most companies obey this _____ but sometimes labels do not show everything that has been added. Very occasionally _______ ingredients are found in food. Decide whether the following statements are true or false : False True 3: Food labels are used to ensure we know what we are eating? False True 2: Flavourings have E-numbers ? False True 1: Food goes off because it reacts with nitrogen in air ?

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