VIRTUAL WATER. Eating water: Context The world’s population is set to go from 7 billion to 9 billion by 2050. Evidence suggests that the more developed.

VIRTUAL WATER

Eating water: Context

• The world’s population is set to go from 7 billion to 9 billion by 2050.

• Evidence suggests that the more developed a nation, the more its people will eat a high-protein meat-rich diet.

• As a result of both these factors, the UN Food and Agriculture Organisation predicts as much as 70% more food will be needed by the middle of the century.

• In the developing world this could be as high as 100%.

• Source: Smith. T (2012) World Water Day: How much water do you use in a day? At http://www.rtcc.org/world-water-day-how-much-water-do-you-use-in-a-day/ Accessed 3.4.2013.

Activity 1:

Virtual water in food

Big idea:

Water is used in many ways to produce food and other items

Curriculum areas: Science, Maths, speaking and listening, Writing,

Prior learning: water cycle, how to divide by 10, 100 and 1000, children to have possibly completed the globe and dinosaur activity. An understanding of the word ‘virtual’ meaning that it is there but we can’t see it.

Resources needed:

1. Plastic, real or pictures of food items on ‘virtual water food’ worksheet with a sticky label attached indicating the answer e.g. glass of milk would have a sticky label with ‘200 litres’ written.

2. One copy of worksheet per child.

3. Interactive White Board to show film clips.

4. Maths follow on questions worksheet.

(Most of the data in this activity is extracted from ‘Virtual Water’ by Tony Allan, an excellent guide to virtual water and problems associated with this).

Watch the ‘all you eat’ video clip which explains how water is used to produce food:

http://www.angelamorelli.com/water/

(Background perspective on virtual water in food)

(nb Scroll down to activate the animation on the webpage)

Activity outline:

Prior to the children entering, hide the items of food around the classroom/playground area.

Create a worksheet indicating ‘virtual water’ in different foods

Children work in pairs to find the items on the worksheet and complete the sheet with how many litres of water each item needs in order to be produced.

Here are some calculations of the water cost of different foods as published in different websites…..

http://graphics.latimes.com/food-water-footprint/

Cereal, 1 cup = 130 litersOrange Juice, 1 cup =170 LCoffee, 1 cup = 140 LCheese, 1 portion = 250 LRice, 100 g = 140 LMilk, 1 glass = 200 LTea, 1 cup = 35 LSugar, 1 piece = 10.5 LLettuce, 1 kg = 130 LApple/Pear, 1, 70= LChicken meat, 150 g = 615 LPork meat, 150 g, 690 LEgg, 1, 135 LBanana, 1, 70 LOlives, 100 g = 250 LOats, 100g = 237 LOnions, 100g = 17 LSoybeans, 100g, = 275 LPineapple, 100g = 42 LChocolate, 100g = 2,400 LCucumber, 100 g = 24 LGrapes, 100 g = 45.5 LLemon, 100 g = 34 LMargarita Pizza = 1,216 LHamburger = 2,400 L

http://news.yahoo.com/check-much-water-needed-produce-food-100848003.html

Everything we eat is flooded with “virtual water,” or water used indirectly to produce food from cradle to grave. In fact, 70% of the world’s water consumption feeds the agriculture industry, and demand for fresh water is increasing at a rate of one trillion liters a year. The GRACE Communications Foundation wants people thinking more critically about the water in their food, and has released a report that includes the average global water footprints for some of our most beloved—and resource-hogging—foods.

1. Slice of pizza = 42 gallons of waterThat would be 18 gallons for the flour, 21 gallons for the cheese, and nearly 3 for the sauce. Mozzarella, it turns out, is a real water suck, as is any animal product. Of course, this is the global average, and water use per slice varies from country to country. French pizza has less than half this footprint, the US just about hits the average mark, and Chinese pizza is slightly more waterlogged.

2. A dozen eggs = 636 gallonsThat’s right, every single egg requires an average of 53 gallons of water to produce. Chickens require water-intensive grain feed (about two pounds per every pound of chicken protein produced) as well as water for drinking and irrigation.

3. A pound of lettuce = 30 gallonsIn general, vegetables take much less water to produce than animal products: That’s why GRACE’s report suggests “Meatless Mondays” as a step to conserve water—you don’t need to go vegan, but every bit helps. Even better news for salad lovers in the US: Lettuce’s footprint is less than half the global average there.

4. A loaf of bread = 288 gallonsWheat is big. Between 1996 and 2005, global wheat production contributed 15% to the total water footprint of all crops. Make that sandwich open-face.

5. A bar of chocolate = 317 gallonsThe report actually calculated the water footprint of a pound of chocolate, but that’s probably more than you eat in a sitting. Or a week, hopefully. But with one pound touting 3,170 gallons of water and a classic Hershey bar weighing 1.55 oz, or about 0.1 lbs, a single candy bar is still pretty wet. Say it ain’t so. You can find more water footprints here, though they’re calculated in litres per kilogram.

http://qz.com/171698/it-takes-53-gallons-of-water-to-produce-a-single-egg/

https://www.pinterest.com/pin/489062840754305215/

http://www.revistaadn.com/website/index.php?option=com_content&view=article&id=333:el-camino-invisible-de-un-bien-preciado&catid=37:noticiasgenerales

Activity 2

Virtual breakfast

Curriculum areas: Science, Geography, Maths

Big idea:

Understand that we consume vast amounts of water that we cannot see.

Prior learning: virtual water in food activity

Activity outline:

Ask the children to write what they would have for a typical breakfast….

Model how you would work out the amount of virtual water in your typical breakfast e.g.

1 slice of toast1 cup of tea1 bowl of cereal and milk

Slice of toast = 60 litres

1 cup of tea = 30 litres

I bowl of cereal (we do not have the data for this but we know it contains wheat, wheat = 500 litres for 500grams, an average bowl of cereal is about 30 grams) = 30 litres of water

Milk in the cereal (200ml glass is 200 litres of water so 100ml in cereal is 200 divided in 2) = 100 litres….

….60 + 30 + 30 + 100 = 210 litres of water consumed in my breakfast!

Imagine a 2 litre bottle of coke, that is 105 of those!

And that is just breakfast!

Children work together to work out how much virtual water they have consumed in their breakfast….

Children then compare with other children on their table….

Breakfast, Lunch and Dinner…?

Breakfast: Cereal, milk, tea/coffee, orange juice…egg and bacon?

Lunch: Cheese and tomato sandwich, packet of crisps, an apple?

Dinner: Burger, chicken, beef steak, rice, pasta, veg?

130L 200L

Tea: 35LCoffee: 140L

170L

600L

GRAND TOTAL=

80L

Source: Allen 2011

Cheese: 250LBread: 40L1 Tomato: 13L

70L185L

LUNCH

• For a lunch another 568 litres of water could be used. By selecting a cheese and tomato sandwich (250 litres for the cheese portion, 40 litres per slice of bread and 13 litres for one tomato) your water footprint is already 343 litres.

• Then if you wanted an apple (70 litres) and a bag of crisps (185) to go along with that you footprint would be higher.

• Once again another cup of tea or glass of juice would further add to your day’s water footprint.

• For dinner if you were to go for a Margarita pizza for example, you could see a footprint of around 1216 litres, or if you wanted a burger, that would be 2400 litres of water.

• Meat could see your footprint vary from 614 litres (100g of chicken meat) to 7000 litres (a beef steak).

• A portion of rice would be 140 litres, while a pasta choice would be 130 litres while adding vegetables to your meal could add another 10.5 litres

2400L

614L7000L

140L 130L 10.5L

M&Ms:1153 l

• If you wanted some chocolate later in the evening, you would add 2400 litres to your footprint for 100g. And if you wanted an evening drink a glass of beer would be around 75 litres and a glass of wine could be 120 litres.

Teacher’s notes

• As a follow up to this activity, children could work out how much virtual water they consume in a whole day.

• Furthermore, if you have a link school in another country, you could ask them to do the same and compare the data.

• Why is it very similar/different?

• What types of food contains more virtual water?

• How are the children’s diets similar/ different?

• Does processed food contain more virtual water?

• Why?

• How could the children reduce the amount of virtual water they consume?

Activity 3:

Trading Water

Conceptual Understanding…

• Water scarcity• Water rich/poor• Peak Water• Virtual water• Types of water• Commodification of water• Water distribution• Fresh water availability

Water Footprint calculatorhttp://www.waterfootprint.org/?page=cal/WaterFootprintCalculator

• Recommendations say people should drink between 2 to 4 litres of water a day.

• For the average person’s daily diet, however, between 2000 and 5000 litres of water is used on average

Source: http://www.rtcc.org/world-water-day-how-much-water-do-you-use-in-a-day/

Trading water to feed your people…

Envelope of coloured squares representing different water footprints.

Keep a record but keep it to yourselves

Trade with each other to feed a growing population

Rules…..

Trading water to feed your people…

• Blue squares represent products like sugar beet, maize, apples, bananas

• Yellow squares represent products like tomatoes, potatoes, lettuce, oranges

• Green squares represent products like beef, pork, chocolate

• Pink squares represent products like pasta, rice, bread

References

• Allen. A (2011) Virtual Water: Tackling the Threat to Our Planet's Most Precious Resource . London. I.B Tauris

• Mekonnen, MM and Hoekstra, AY (2011) National water Footprints Accounts : The Blue, Green and Grey water Footprint of production and consumption, Volume 1: Main Report. Value of water: Research Series No. 50. UNESCO- IHE Institute for Water

• The Guardian newspaper Wednesday March 12 2012• http://

www.rtcc.org/world-water-day-how-much-water-do-you-use-in-a-day

• http://www.worldmapper.org/index.html