grade 8 science unit 1: water systems on earth chapter 1 water is located everywhere on the planet...
TRANSCRIPT
Grade 8 ScienceUnit 1:
Water Systems on Earth
Chapter 1 Water is located
everywhere on the planet however only part of the water
can be used .
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.
Review of Terms...
Definition of Lithosphere: the solid rocky ground of the Earth’s crust.Do not write in pamphlet
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
Oceanographer: A person who studies all aspects of the ocean. They are concerned with the biology, geology, physics, and mathematics of the ocean.
The constant cycling of water through the processes of : Evaporation & Condensation.co
ndensatio
Water is constantly changing from
(gas liquid) and back again. This driven by the sun’s energy.
Ocean Water vs. Fresh Water
Three ways in which fresh water differs from ocean water are:
CHART 1. Salinity
2. Density
3. Freezing point
1. Salinity - Definition-The amount of salt dissolved in a specific amount of water.
Beach Area Sodium Chloride -salt
salt comes from dissolved solids in the ground and volcanoes.
salt comes from dissolved solids in the ground and volcanoes.
Fresh Water has tiny amounts of
salt.
Salt Water Average amount of
salt in salt water is 35 ppt.
Amount of salt found varies depending on location.
Increase salt at the equator and north and south poles
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.
3. Freezing Point -Definition
-The temperature at which a liquid freezes.
*Fresh water... 0oC* Salt water... -1.9oC
Core Lab Activities
Activity 1-3A“Salinity’s Effect on Water
Density”
Graphing Assignment pp60-61
“Temperature & Water Density”
Sources of Fresh Water1. Lakes, ponds and
wetlands2. Streams and rivers3. Ground water4. Run Off5. Glaciers6. Drainage Basins
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”.
Factors that Affect Run Offtext pp 27-28
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.
5.Glaciers...A moving mass of snow and ice.
Found in areas where it is so cold the snow remains all year.
Glaciers slow down the Water Cycle by storing big amounts of frozen fresh water.
Some water thaws in the hot summer months.
They give us information about the Earth’s past climates. ( samples)
The Ice Age
The most recent began 120 000 years ago ending
11 000 years ago.Glaciers covered ~ 20% of land on Earth.
Glaciers and Global WarmingIn 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.
WatershedsThe 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.
6.Drainage Basins
6 Major Drainage Basins in NL1. Labrador Sea 2. Gulf of St. Lawrence3. West Coast Gulf of St.
Lawrence4. South Coast Gulf of St.
Lawrence5. Atlantic Ocean Avalon
Peninsula6. Atlantic Ocean North-east
Coast
Continental Divide
Seperates the Pacific Ocean Drainage Basin from the:
Gulf of Mexico BasinArtic BasinAtlantic BasinHudson Bay Basin
Turn to Activity on page 31 in textbook.
One Component Affects Another
Salinity :affects the types of organisms that can survive in an area. Eg. Dead Sea
Temperature :
affects the amount of dissolved oxygen in water. Ex. The colder the water the more oxygen.