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Grade 7 Science Fusion Unit 2

Terms in this set (2)

what percent of earths water is drinkable
3%

what percent of drinkable water is in polar ice caps?
75%

all weather is related to what? (hint: it moves all the time from the earths surface to the atmosphere. It forms clouds, water falls back to the earth, then evaporates back up)
water

what can reshape a landscape? (hint: like wear away a rock)?
water

what depends on water?
everything

what is the structure of a water molecule
matter is made of tiny particles called atoms. atoms join to make molecules. Water is molecules of 2 hydrogen atoms and one oxygen atom.

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polarity
anything that has a positive charge at one end and negative charge at the other end

what is the only planet in the solar system with abundant liquid?
Earth

what is water vapor?
a gas, so most water is found in Earth's atmosphere

what is less dense? solid water (ice) or liquid?
solid water...so ice floats because it is less dense then the liquid water

cohesion
a property that holds molecules of a substance together (that is, it sticks to itself)

adhesion
a property that holds molecules of different substances together (that means that is sticks to other substances)

specific heat
energy needed to heat a substance by a particular amount

solvent
a liquid that dissolves substances

what is the universal solvent?
water. it dissolves many things.

what characteristics of water gives it its properties of adhesion, cohesion, high specific heat and solvent
it has polarity

water gets soaked up by a paper towel because of what property?
adhesion

because water can dissolve most substances, it is commonly used as what?
a solvent

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what are the four major roles of water on earth?
shaping the earths surface
supporting life
supporting human activities
influencing weather

a large amount of energy is required to change waters temperature. true or false?
true. water has a high specific temperature, so it needs a lot of energy to heat up.

water cycle
movement of water in the Earth's system

hydro
water

hydrologic cycle
atmosphere
lithosphere
hydrosphere
biosphere

atmosphere
gas surrounding the earth (sky)

lithosphere
solid outer shell of Earth

hydrosphere
parts of earth that are water

biosphere
living things on earth

melt
solid to liquid

evaporate
liquid to gas

sublimate
solid to gas

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condense
gas to liquid

freeze
liquid to solid

three ways water reaches atmosphere
evaporation, transpiration and sublimation

evaporation
liquid water changes into water vapor

transpiration
release of water vapor into the air by plants

sublimation
water changes directly to water vapor without first becoming liquid

condensation and precipitation
what happens to water in atmosphere

condensation
change in the state of gas to liquid

precipitation
any form of water that falls to the Earth from clouds

runoff and infiltration, ice flow, ocean circulation
how water moves on land and in the oceans

runoff
Water that flows over land. Examples are streams, rivers. All water flows downhill due to gravity. Runoff goes toward oceans and lakes

infiltration
water on land that seeps into the ground

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groundwater
water that is underground

energy and matter
what the water cycle transports

energy
transported in water cycle through changes of state and movement of water from place to place

matter
solids and liquids transported in water

surface water
water above Earth's surface

groundwater
water found in the spaces between rock particles below the Earth's surface

water table
upper boundary (or surface) of groundwater
Most of the drinking water in the USA comes from groundwater.

channel
the path that a stream of water flows

tributary
smaller stream that feeds into a river and eventually into a river system

watershed
area of land drained by a river system

divide
an area of higher ground that separates watersheds from one another

gradient
measure of the change in elevation over a certain distance (it is the steepness of the land)

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flow
the amount of water that moves through a river channel in a given amount of time (flow increases during a storm and decreases during a drought)

stream load
materials carried by a stream

aquifer
body of rock that stores groundwater and allows it to flow

pores
how an aquifier stores water...pores are the open spaces water is stored in

porosity
storage space in pores

permeability
measure of how easily water can flow through an aquifer. High permeability means many pores are connected, so water can flow easily.

recharge
surface water that trickles down into the ground and reaches a water table and enters an aquifier.

recharge zone
where recharge occurs

discharge
process where ground water becomes surface water. this happens in discharge zones.

how surface water is used
1. drinking and home use
2. agriculture
3. industry
4. transportation and recreation

ocean currents
streamlike movements of water in the ocean

surface currents
ocean currents that occur near the surface of the ocean, caused by wind

3 factors affect surface currents
1. Continental deflections
2. Coriolis effect
3. global winds

continental deflections
when surface currents reach continents, currents are deflected and change directions

Coriolis effect
deflection of moving objects from a straight path due to Earth's rotation. Simple words: it causes currents to move in a curved path instead of straight.

global winds
winds that blow across the surface of Earth's oceans

deep currents
movement of ocean water way below the surface

density
amount of matter in a given space or volume

salinity and temperature
two factors that affect water density

temperature
cold water is denser that hot water

salinity
measure of amount of dissolved salts or solids in liquid. the higher the salinity, the more dense the water.

how convection currents transfer energy
-water at surface absorbs energy from sun
-surface currents carry this energy to colder regions
-the warm water then cools
-as it cools, it becomes denser and sinks
-the cold water travels along the ocean bottom
-then, cold water rises to surface and as warm water moves away
-cold water absorbs sun, and then it starts all over again

convection current
movement of water that results from density difference.
Surface currents and deep currents are linked in the ocean. Together they form convection currents.

upwelling
when warm surface water is replaced by cold, nutrient rich water from the deep ocean

phytoplankton and zooplankton
food chain starters supported by nutrients in upwelling

how deep currents form
heat rises and cold water sinks

why does the South Equatorial current change?
because it deflects off of South America

surface water
any water above ground

groundwater
found under Earth's surface

permafrost
water frozen in a layer of soil in polar regions

water quaility
measure of how clean or polluted water is

water supply
availability of water

water supply system
carry water from groundwater or surface water for people to drink

water pollution
waste or other organisms added to water so it is harmful

two types of water pollution sources
point-source
nonpoint-source

point-source pollution
pollution that comes from one specific site

chemical pollution
when harmful chemicals are added to water

nonpoint-source pollution
comes from many small sources and is difficult to control Usually comes from city streets, roads, drains and mines

thermal pollution
heating of natural water from human activity. Warmer water has less oxygen available for organisms that live in that water.

acid rain
a form of chemical pollution that occurs when gases from burning fossil fuels mix with water in the air.

biological pollution
live or dead organisms added to water

wastewater
water used by people for flushing, showering or washing dishes

eutrophication
increase in the amount of nutrients in water that occurs naturally

potable
water suitable to drink

artificial eutrophication