1. Unit 1: Water Systems on Earth
Grade 8 Science
Unit 1:
Water Systems on Earth

2. Effects of Water?
Churchill River

3. Large Ocean Wave

4. Recreational Activities
How do you use water?
House Hold Use
Personal Use
Recreational Activities

5. Water Distribution

6. Only 3% of the Earth’s water is fresh water (no salt).
2/3 of this water is frozen in ice sheets.
Therefore only 1% of the fresh water on Earth is available.

7. Review of Terms...
Definition of Lithosphere: the solid rocky ground of the Earth’s crust.
Do not write in pamphlet

8. Atmosphere: the environment surrounding the Earth.
Do not write in pamphlet

9. Hydrosphere: All water on Earth
Hydrosphere: All water on Earth. Including that in the lithosphere and atmosphere.

10. Scientists who study water...
Hydrologist
A person who studies Earth’s water systems and helps to find solutions to problems of water quality and quantity.
Not in pamphlet

11. Oceanographer: A person who studies all aspects of the ocean
Oceanographer: A person who studies all aspects of the ocean. They are concerned with the biology, geology, physics, and mathematics of the ocean.

12. Why do We Not Run Out of Water??
Because of the:
WATER CYCLE

13. The Water Cycle...

14. The constant cycling of water through the processes of :
Evaporation&Condensation.condensa tio
Water is constantly changing from
(gas liquid)
and back again. This driven by the sun’s energy.

15. Ocean Water vs. Fresh Water
Three ways in which fresh water differs from ocean water are:
1. Salinity
2. Density
3. Freezing point

16. 1. Salinity - Definition
-The amount of salt dissolved in a specific amount of water.
salt comes from dissolved solids in the ground and volcanoes.
salt comes from dissolved solids in the ground and volcanoes.

17. Fresh Water Salt Water has tiny amounts of salt.
Average amount of salt in salt water is 35 ppt.
Salt content varies depending on location.
Increase salt at the equator and poles

18. 2. Density - Definition
-The amount of mass of a substance in a certain unit volume. *How tightly packed together the material is in a substance.

19. *Ocean water is more dense than fresh water due to the salt content.
The Dead Sea

20. 3. Freezing Point -Definition
-The temperature at which a liquid freezes.
*Fresh water... 0oC
*Salt water oC

21. Core Lab Activities Activity 1-3A “Salinity’s Effect on Water Density”
Graphing Assignment pp60-61
“Temperature & Water Density”

22. Sources of Fresh Water Lakes, ponds and wetlands Streams and rivers
Ground water
Run Off
Glaciers

23. 3. Ground Water...
Precipitation that falls on land and sinks out of sight.
Sinks through pores in rocks and goes down to bedrock where it pools.
These pools to us make up “wells”.

24. Ground Water : Drilling Wells

25. 4. Run Off
Water that doesn’t sink into the ground or evaporate and flows over the land.
Run-off is affected by:
a) ground material,
b) amount of rain,
c) amount of time it rains,
d) slope (steepness) of the land,
e) vegetation,
f) the amount of development.

26.
Glaciers

27. 5.Glaciers...
A moving mass of snow and ice.
Found in areas where it is so cold the snow remains all year.

28. Glaciers
A glacier is any large mass of ice that moves slowly over land.
*Glaciers only form in areas where more snow falls than melts
*Snow builds up year after year
*Pressure on the snow at the bottom turns it into ice
*Gravity pulls the glacier downhill

29. Types of Glaciers Valley glacier Continental glacier
pubs.usgs.gov/of/2004/1216/images/mendenhall.gif

30. Types of Glaciers
A valley glacier is a long, narrow glacier that forms high in a mountain valley
*Also called Alpine glaciers
*flows a few centimeters to a few meters per day
A continental glacier is a glacier that covers much of a continent or large island
*much larger than valley glaciers
*spreads out like pancake batter
*cover Antarctica and Greenland

31. Glaciers in mountains and on the continent of Antarctica

32. Glaciers flow until they reach an ocean, where crevasses open and icebergs fall off

33. Water trapped in glacial ice

34. Importance of Glaciers
Almost 69% of all fresh water on Earth is found in glaciers
Glaciers slow down the Water Cycle by storing large amounts of frozen fresh water. (=Reservoir)
Some water thaws in the hot summer months.

35. Importance of Glaciers
Glaciers give us information about the Earth’s past climates. ( samples)

36. Continental Glaciers
Continental glaciers cover about 10% of Earth’s surface
The glacier covering Antarctica is over 14 million square kilometers and 2 kilometers thick
An Ice Age is a time when continental glaciers cover large parts of Earth’s surface
* The last ice age ended 10,000 years ago.
* Ice has covered 1/3 of Earth

37. The Ice Age
The most recent began years ago ending years ago. Glaciers covered ~ 20% of land on Earth.

39. Glaciers and Global Warming
In the last 100 years the average surface temp. Has increased by 0.5oC.
The world’s glaciers are melting at a quicker paces than ever before.

40. Melting Greenland Glacier

41. Receding Athabasca Glacier in Alberta
It has receded 1.5 km since 1843.

43. What does this mean? Ocean waters may rise Flood rivers
If they disappear, rivers may dry up.

44. Watch the video Chasing Ice

45. Watersheds and Drainage Basins

46. 6.Drainage Basins Watersheds
The area of land with water that drains into a body of water such as a river, pond, lake or ocean.
There may be many smaller basins within a larger basin.

47. A divide separates one drainage basin from another.
For example:
The Continental Divide

49. Canadian Drainage Basins

50. Drainage basins close to home are Labrador Sea, & Gulf Of St. Lawrence

51. 6 Major Drainage Basins in NS
Labrador Sea
Gulf of St. Lawrence
West Coast Gulf of St. Lawrence
South Coast Gulf of St. Lawrence
Atlantic Ocean Avalon Peninsula
Atlantic Ocean North-east Coast

52. Our Drainage Basin
Tracadie River Basin

53. One Component Affects Another
Salinity :
affects the types of organisms that can survive in an area. Eg. Dead Sea

54. Temperature :
affects the amount of dissolved oxygen in water. Ex. The higher the temp. the more oxygen.

55. The convergence of the Labrador Current and the Gulf Stream Current (place where they meet)
influences productivity of the Grand Banks (more fish there), the movement of icebergs, and migration of capelin and whales.