‘Water, Water Everywhere nor any drop to drink…’
Today’s class is about where water is… and how much of it we actually have access to…
1
Read the following extract from Bill Bryson’s ‘A short History of Nearly
Everything’…
“There are 1.3 billion cubic kilometers of water on earth and that is all we are
ever going to get. The system is closed: practically speaking nothing can be added or subtracted. The water
you drink has been around doing its job since the Earth as young. By 3.8 billion years ago the oceans had (a
least more or less) reached their present volumes.
The water realm is known as the hydrosphere and it is overwhelmingly oceanic. 97% of all the water in the
world is in the seas, the greater part of it in the Pacific, which is itself bigger than all the land masses put
together. Although the pacific holds just over half of all the ocean water (51.6%); the Atlantic has 23.6% and
the Indian Ocean 21.2% leaving just 3.6% to accounted for by all the other seas. The average depth of the
oceans in 3.6Km with the Pacific on average 300m deeper than the Atlantic and Indian Oceans. 60% of the
Earth surface is ocean more than 1.6Km deep… as Philip Ball noted we would be better calling or planet not
Earth but Water!
Of the 3% of the Earth water hat is fresh, most exists as ice sheets. Only the tiniest amount – 0.036% - is
found in lakes, rivers and reservoirs, and an even smaller amount – just 0.001% - exists in clouds as vapour.
Nearly 90% of the planet’s ice is in Antarctica, and most of the rest is in Greenland. Go to the South Pole
and you will be standing over 2 miles of ice, at the North Pole just 15 feet of it. Antarctica alone has 6 million
cubic mils of ice – enough to raise the Oceans by a height of 200 feet if it al melted! But if all the water in the
atmosphere fell as rain evenly everywhere the oceans would raise only about a couple of centimeters. “
2
Extract the information about how much water is available in the Earth and create a labeled graph to show
the amounts / percentages of water stored on Earth… but particularly how little fresh water is accessible to
humans to use.
3
Now watch the video clip from ‘How many people can live on planet Earth’ and answer the questions on the
associated sheet. (The important bit starts about 4 mins in!)
http://www.youtube.com/watch?v=B498dbsireA
4
Using your information from the video and the following table… create a visual representation of water usage…
(You could do some extra research on this and add your own water consumption statistics for other activities!)
5
a.
Flush Toilet
13litres
b.
Brush teeth / shave / wash hands
c.
5 min shower
d.
Water garden / lawn
e.
Grow an orange
50
f.
Grow an apple
70
g.
Take a bath
80
h.
Washing machine cycle (efficient) 44
i.
Produce an egg
j.
Produce one liter of bottled water 5
5
30
50
200
Now use the maps of population, poverty and water resources to create your own annotated map that
represents problems of water demand and supply on a global level. Think carefully about specific countries
and heir wealth and how that enables them to overcome water stress.
6
In Pairs:
Now use the web link
http://earthtrends.wri.org/searchable_db/index.php?theme=2&variable_ID=694&action=select_countries
to find regional water resource data and pick one region to display the data so it shows countries and heir
water situation clearly. Try to complete an annotated map of the region that can be displayed to show
particular water problems in countries and regions.