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Science8
Water unit test
Question | Answer |
---|---|
What percent of water in the world is fresh water? | Less than 1% |
Fresh water means | Water that contains a low concentration of dissolved salt and can occur in any 3 state |
The word fresh water doesnt mean that it is | Drinkable or potable |
Most liquid fresh water does contain | Living organisms and chemicals |
Salinitity means | Average concentration of salt |
The salinity of ocean water is | About 3.5% |
Salt water can be found in | Marshes, bogs, estuaries and swamps |
Salt swamps and salt marshes occur when | Ocean waters come onto shore lands and fill low lying areas or depressions |
Salt swamps have | Trees |
Salt marshes have | Grasses |
Estuaries are affected by the ocean With | Tidal action |
______ push ocean water inland to mix with fresh water | High tides |
The mix of salt and fresh water is called | Brackish water |
Some inland salt lakes like the _________ are actually more salty than ocean water | Dead sea |
Draw a picture of an estuary | River ----> Brackish <---- Ocean |
Swamps, marshes and bogs are | Wetlands that filter and clean fresh water |
Wetlands help to | Moderate water levels in times of drought or flooding |
Bogs are dominated by | Mosses |
__% of the worlds water exists as solid form in glaciers, polar ice caps and snow/hail | 2% |
_____ from glaciers is an important source of freshwater | Melted water |
Liquid water absorbed by the roots of plants passing out through leaves as water is a process called | Transpiration |
evaporation(a)is | water changing into water vapor by heat from the sun |
condensation(b)is | cooled water vapor in the air becoming liquid again |
transpiration is | water evaporating from plants |
precipitation(c)is | too much water gathering in the clouds so the air currents can no longer keep it aloft, eventually falling back to earth. |
sublimation(d)is | layers of snow that have been frozen for years accumulating and their pressure turns the bottom layer to ice, forming a glacier.some snow and ice at the top can turn directly back into water vapor |
runoff(e) is | water flowing off the surface of the ground |
estuaries(f) are | areas where fresh water from rivers and salt water from oceans mix to form moderately salty or brackish water |
marshes(g) are | low-lying treeless areas of soft wet ground that is usually covered by water for at least part of the year. They may contain fresh or salt water and are characterized by the grasses and plants that live there. |
swamps(h) are | like marshes but swamps contain trees and shrubs |
deserts(i) are | sometimes found on mountain sides, air loses much of its moisture as it blows over mountains, therefore little precipitation falls on the leeward side of a mountain |
ground water(j) is | water that has soaked into the earth and has passed through gravel, sand, soil, rock on its way back to rivers, lakes. |
the water in lakes/oceans(k) is | not the same as it was when it evaporated. even the precipitation may contain acid or other chemicals. because water can dissolve substances in both liquid and vapour form, things can be carried through ground and surface water into lakes/oceans. |
runoff carries | sediment |
_________ help to hold down vegetation | plant roots |
ploughing removes vegetation over a ____ term basis | short |
clear cut logging removes vegetation over a ____ term basis | long |
deposition: | sediment settling to the bottom of a river. |
deposition can form: | deltas on river mouths |
deposition and deltas are removed by: | dredging |
floods are caused by: | excessive rainfall, or rough waves along coastal lowlands, or a dam bursting |
floods are dangerous if you live in | flood plains or areas of torrential rainfall |
leeves are built | parallel along riverbanks, to keep the river contained |
dikes | protect land that has been reclaimed from the ocean, sometimes built around houses or towns prone to flooding. |
avalanche ______ carefully monitor areas known for avalanches | patrols |
snow on a mountain may be _______ by the wind and repeated freezing and thawing may cause _______. | undercut, fracture lines |
beginning: the water table (a): | rain strikes the ground, the attraction of water molecules to soil particles causes rain to spread outward. |
percolation: the water table (b): | percolation: gravity causes water to sink through the ground, dissolving salts and minerals on the way |
aquitard: the water table (c): | aquitard: an impervious layer of clay, slit or rock that will not allow water to pass through fast enough to be a water supply |
saturated zone: the water table (d): | saturated zone: as more rain falls, water completely fills the spaces above the impervious layer, saturating the soil. |
the water table (e): | the water table: the upper layer of the saturated zone. |
wells- the water table (f): | wells must reach the saturated zone |
aquifer- the water table (g): | aquifers: large accumulations of water in the ground and soil, but can be depleted like oil deposits. |
how do wells work? | it is pumped to and distributed through electric or fuel powered pumps. |
waste water flows into | a septic tank |
in a septic tank, the larger solids settle to form a | sludge with the effluent above it |
how does the effluent leave a septic tank? | flows through pipes into a septic or tile bed. |
what is a tile bed? | consists of pipes with small holes, allowing the effluent to pass into the ground. |