Transcript Water in Earth’s Processes
Water in Earth’s Processes
Lesson 10
A Wet Planet
EQ: How is Earth’s water distributed among saltwater and freshwater?
How is Earth’s water distributed among saltwater and freshwater
• Some people call Earth the “blue planet” because over with water.
70%
of Earth’s surface is covered •
Most
of Earth’s
polar ice caps freshwater
is found in the near the North and South Poles.
• From largest to smallest, the amounts of water on Earth are
salt water (97%), solid fresh water (2%), liquid fresh water (1%).
Salt Water
• Most of the water on Earth is in Earth’s oceans • Oceans contain salt water.
• The salinity, or salt concentration, averages about 3.5%, or 35 grams of salt per kg of water.
• In order of size from largest to smallest, Earth’s oceans are the Pacific, Atlantic, and Indian Oceans.
Fresh Water
• Most of the Earth’s freshwater is located in the polar caps.
• Lakes, rivers, streams, and glaciers hold the rest of Earth’s surface freshwater.
• A glacier is a very slow moving river of ice.
• A large portion of the rest of Earth’s freshwater is trapped between underground layers of rock. This trapped freshwater is called groundwater.
Quick Check
About how much of Earth’s surface is covered by water?
A. 0% B. 30% C. 70% D. 100%
Quick Check
From the largest to smallest, the amounts of water on Earth are A.
liquid fresh water, solid fresh water, salt water.
B. salt water, solid fresh water, liquid fresh water.
C. salt water, liquid fresh water, groundwater.
D. groundwater, salt water, solid fresh water.
Quick Check
A glacier is A. a river of liquid water.
B. an ice cap.
C. a solid lake.
D. a slow river of ice.
Lesson 25
Sun, Wind, and Water
EQ: How does a drop of water move through the water cycle?
Wind
• Earth receives heat energy from the sun through Radiation.
•
Radiation
is the
empty space
.
movement of energy
through • Air at different places on Earth heats up unevenly. The uneven heating up of Earth’s air is what produces wind.
• Cool air moves toward warmer air. Warm air moves away from cooler air.
Moving air is wind
.
Water
• Very little water is ever lost on Earth • The
sun
is the drives the
source of energy water cycle
.
that • Energy from the sun
particles
to
causes move faster
into the air as
water vapor
.
the
water
and escape
Water
• • • • Water vapor rises into the air and cools down. The water molecules move
closer
together, or
condensation
.
slower condense
and come . This is called
Condensation
forms clouds and such as rain, sleet, hail, and snow.
precipitation
The
precipitation falls
to the ground and gathers there in puddles, ponds, rivers, lakes, and oceans. (Accumulation) Some water seeps into the ground and collects there. This
underground water groundwater
. (runoff) is called
Water
• Some
groundwater
finds its way into oceans.
• Water on the surface is warmed again by the sun and will evaporate. So will water in the soil.
• Water vapor also enters the air from plants. This is called
transpiration
.
• This keeps the water cycle going.
Quick Check
What is the source of energy that produces winds and causes evaporation?
A. lightning B. Earth’s rotation C. the moon D. the sun
Quick Check
Heating liquid water produces A. snow.
B. rain.
C. water vapor.
D. groundwater.
Quick Check
The sun’s energy reaches Earth through A. evaporation.
B. condensation.
C. radiation.
D. wind.
Quick Check
What process produces rain?
A. condensation B. evaporation C. warming D. solidification
Quick Check
Water vapor is a A. liquid B. solid C. gas D. form of energy
Quick Check
The cooling of water vapor leads FIRST to A. cloud formation.
B. evaporation.
C. formation of groundwater.
D. precipitation.
Quick Check
What process produces a cloud?
A.
B.
C.
D.
Evaporation Condensation Radiation warming
Lesson 11
The World’s Oceans
•
EQ: How does the composition and topography of earth’s oceans vary by location?
Location of the World’s Oceans
• The Pacific Ocean is the largest ocean. It is bordered by North America, South America, Asia, Australia, and Antarctica • The Atlantic is the second largest ocean. It is bordered by N. America, S. America, Africa, Europe, and Antarctica.
• The third largest ocean is the Indian Ocean. It lies between the countries of India, Pakistan, Australia, and the continents of Africa and Antarctica.
Composition of the World’s Oceans
• The main substance dissolved in ocean water is sodium chloride (NaCl) or table salt.
• Other dissolved solid substances are sulfate, magnesium, calcium, and potassium.
• Solid substances dissolved in sea water come from rivers, streams, rocks from the shore, volcanoes and underwater hot springs.
• The concentration of all the dissolved substances in sea water is about 3.5%.
Composition of the World’s Oceans
• The oceans also hold dissolved gases, such as oxygen and carbon dioxide.
• Marine life such as fish need dissolved oxygen in sea water to live.
• Sea plants such as seaweeds need carbon dioxide to survive. They get it from the dissolved carbon dioxide in sea water.
Topography of the World’s Ocean Floor
• Oceanographers have mapped the ocean floors by using special equipment.
• Echo sounding, (pings), measure the time it takes a pulse of sound to go from the ship to the ocean floor and echo back to the ship.
• The speed of sound in sea water averages about 1520 m per second.
Quick Check
Which continents border the Atlantic Ocean?
A. North America, South America, Asia, Australia B. Asia, Australia, Africa C. North America, South America, Europe, Africa D. South America, Europe, Asia, Australia
Quick Check
Which substance do fish need to live and take in from water that you take in from air?
A. salt B. oxygen C. carbon dioxide D. water
Quick Check
Pings from an echo sounder aboard a ship make a round trip in 8 seconds. How far beneath the ship is the ocean floor?
A. 2,920 meters B. 6,080 meters C. 11,680 meters D. 23,360 meters
Quick Check
Which shows the order of Earth’s three major oceans from largest to smallest?
A. Pacific, Atlantic, Indian B. Atlantic, Pacific, Indian C. Indian, Atlantic, Pacific D. Atlantic, Indian, Pacific
Quick Check
If you were to walk along the ocean bottom from a beach, which of the following features would you reach after the continental shelf?
A. the abyssal plain B. a seamount C. the mid-ocean ridge D. the continental slope
Quick Check
About how deep is the deepest pat of the world’s oceans?
A. 4000 meters B. 8000 meters C. 11,000 meters D. 14,000 meters
The Water Cycle
Section 11-1 • • • • How is Earth’s water distributed among saltwater and freshwater resources?
How does Earth’s water move through the water cycle?
Explain the steps of the water cycle.
How do people and other living things use water?
Water on Earth
• Most of Earth’s water is saltwater (97%) • Most saltwater is found in the oceans • Only about 3% of water is freshwater • All living things must share about 1% of the total amount of water on Earth
Distribution of Water on Earth
• • • Saltwater oceans and (salt) lakes (97%) Freshwater (3%) – Ice (76%) – Shallow Groundwater (12%) – Deep Groundwater (11%) – Lakes and rivers (.34%) – Water Vapor (0.037%) All living things share less than 1% of total water on Earth!
The Water Cycle 1
• • • Water is naturally recycled through a process known as the water cycle Water moves from bodies of water, land, and living things from Earth’s surface, up to the atmosphere and then back to Earth’s surface.
Steps for the water cycle are: evaporation, condensation, and precipitation
The Water Cycle 2
• • • The source of energy that drives the water cycle is the SUN!
Clouds formation – water vapor loses energy, cools down, condenses into liquid water droplets, droplets clump together around tiny dust particles, forming clouds Most evaporated water comes from oceans, and most precipitation falls back into the oceans
• • •
The Water Cycle 3
Evaporation – the process by which liquid water on the surface change to a gas – Water vapor also enters the air from plants. This is called
transpiration
.
Condensation – process by which gas molecules change into a liquid. This process forms clouds Precipitation – process in which clouds become too heavy to hold the water droplets, and the droplets fall to the Earth’s surface as rain, sleet, snow or hail
• • • • •
How Do People Use Water?
Humans use water for household purposes, agriculture, industry, transportation, and recreation.
Irrigation is the process of supplying water to areas for growing crops Industry – to make products, cool off machines Transportation – travel upon the oceans, lakes and rivers Recreation – exercise and sports
Water and Living Things
• • • Water is important for living things to grow, reproduce and carry on other essential processes.
Photosynthesis – plants use water, carbon dioxide and sunlight to make their own food Habitat – place an organism lives and provides the things it needs to survive
Answers to The Water Cycle
1.
2.
3.
4.
5.
6.
7.
A = precipitation B = condensation C = evaporation The sun Transpiration is the process in which the leaves of plants give off water Water vapor cools, cold air causes water to condense, water droplets clump together around tiny dust particles, causing clouds to form The oceans are where most precipitation falls and where most evaporation takes place Groundwater irrigation
Quick Check
More than 97% of Earth’s total water supply is found in A. ice sheets.
B. groundwater.
C. the atmosphere.
D. the oceans.
Quick Check
The energy the drives the water cycle comes from A. the sun.
B. the Earth.
C. the rain.
D. oceans.
Quick Check
Rain that falls on a steep, paved street during a thunderstorm would most likely be A. groundwater.
B. runoff.
C. a spring.
D. a reservoir.
Quick Check
More than two-thirds of Earth’s freshwater is found in A. rivers and streams.
B. ponds and lakes.
C. glaciers and icebergs.
D. wetlands.
Quick Check
How does the water cycle renew Earth’s supply of fresh water?
A. evaporation.
B. condensation C. the sun D. precipitation
Ocean Water Chemistry
• • • • How salty is ocean water? (3) How do the conditions in the ocean change with depth? (3) How did the ocean form, and how is it currently divided? (8) Describe one factor that increases the salinity of seawater and one factor that decreases salinity. (2)
The Salty Ocean
• The average amount of salt in ocean water is about 3.5% or 35 grams of salt per one kilogram of water • • Ocean water carries many different dissolved salts Sodium Chloride (table salt) is the most abundant salt in the ocean _________________________________________________________________________________ • Factors increasing salinity include evaporation and freezing; • factors decreasing salinity include precipitation and rivers dumping water into oceans ________________________________________________________________________________ • Most oxygen in oceans come from the atmosphere because it is closer to the surface of the water.
The Salty Ocean
• • • • Two gases found in the oceans are necessary for living things: oxygen and carbon dioxide Temperature decreases in the ocean with depth Pressure increases with depth in the ocean Scuba divers are prevented from descending farther than 40 m because of pressure
How Did the Oceans Form?
• • • About 4 billion years ago, the Earth cooled enough for water vapor to condense.
The water began to fall as rain.
The rain filled the deeper levels of Earth’s surface and the first oceans began to form.
Divisions of the Global Oceans
• • • • • Pacific- the largest ocean; getting smaller Atlantic- the second largest; getting larger Indian- third largest; Southern- located along the border of Antarctica Artic- smallest ocean; most oceanographers consider it as an extension of the Pacific, Atlantic, and Indian Oceans
Arctic Ocean Arctic Ocean Arctic Ocean Pacific Ocean North Atlantic Ocean South Atlantic Ocean Indian Ocean Pacific Ocean Southern Ocean Southern Ocean Southern Ocean
Characteristics of Ocean Water
• • • • • • Ocean water is salty Chock-full of solids Climate affects salinity Water movement affects salinity Temperate zones Surface temperature Changes
Ocean Water is Salty
• • • Most of the salt found in oceans is chloride (table salt).
sodium Salts have been added to the oceans for billions of years by running waters (rivers, streams) which dissolve various minerals, and then dump the water into the oceans.
Also, solid materials come from volcanic eruptions, hot springs, ocean waves crashing against rocks
Chock-Full of Solids
• • • • Salinity- the measure of the amount of dissolved salts in a given amount of water.
Measured in grams (g).
1 kg (1000 g) of ocean water carries an average of 35 g of salt (3.5%).
During the water cycle, fresh water from the ocean is evaporated leaving only the salts behind.
Climate Affects Salinity
• • • • Some parts of the ocean are saltier than other parts of the ocean.
Coastal waters in places with hotter, drier climates have a higher salinity.
Coastal waters in places with cooler, more humid climates have a lower salinity.
Main reason: evaporation • Coastal waters in general have less salinity because more fresh water from rivers run into the oceans in these areas.
Water Movement Affects Salinity
• • • Some parts of the ocean (bays, seas, gulfs) move less than other parts.
Also, some parts of the open ocean that do not have currents run through them can be slow moving.
Slower-moving areas of water develop high salinity.
Temperate Zones
• • • • • Temperature of ocean water decreases with depth.
Water in the ocean is divided into three layers by temperate.
Top layer (surface zone) Middle layer (thermocline zone) Bottom layer (deep zone)
Temperature Changes
• Temperature in the surface zones vary with latitude and the time of the year.
• Parts of the ocean along the equator are warm because it receives more direct sunlight per year than areas closer to the poles.
Answers to Ocean Water Chemistry
5.
6.
7.
8.
1.
2.
3.
4.
Surface to about 200 m 17.5
°C Transition zone Bottom of surface zone to 1 m Deep zone 3.5°C 35g of salt per 1 kg of water Precipitation, rivers,
evaporation, freezing
9. Ocean water because it contains salt 10. Sodium chloride 11. Because this is where oceans meet the atmosphere and where algae live 12. The pressure of the water 13. Submersible 14. Water column
Quick Check
Ocean water is more dense than freshwater at the same temperature because of A. pressure.
B. salinity.
C. the Coriolis effect.
D. upwelling.
Quick Check
The most common substances dissolved in ocean water are A. sodium and chloride.
B. potassium and chloride.
C. potassium and sodium.
D. calcium and chloride.
Quick Check
The concentration of all dissolved substances in seawater is 3.5%. How many grams of dissolved substances are in 200 grams of saltwater?
A. 3.5
B. 7.0
C. 57 D. 200
Quick Check
What is the salinity of saltwater?
As you descend deeper into the ocean temperature _____________ and pressure __________.
The two sources of oxygen in ocean water are __________ and __________.
Exploring the Ocean
EQ: What are some features of the ocean floor?
What factors make ocean floor research difficult?
• • • Because of darkness, cold, and extreme pressure, scientists had to develop new technology to enable them to study the deep ocean floor.
SONAR stands for sound navigation and ranging.
Oceanographers study the oceans by: sonar -satellite
What are some of the features of the ocean floor?
• The eight features of the ocean floor are: – Continental shelf : a gentle sloping, shallow area of the ocean floor that extends outward from the edge of the continent.
– Continental slope : marks the true edge of a continent, a steady slope where rock that makes up the continent stops and the rock that makes up the ocean floor begin.
– Seamounts : mountains completely under water; extinct volcanoes
What are some of the features of the ocean floor?
– Abyssal plain ocean floor.
– Guyot : smooth, flat region of the ocean floor – Mid-ocean ridge – Volcanic Island : a continuous range of mountains that wind around Earth’s ocean floor.
: very tall mountains created by the cooling and hardening of erupting volcanoes on the – Deep-sea Trench : canyons on the ocean floor that are the deepest spots on Earth.
- flat-top mountain flattened by the action of waves – SONAR stands for sound navigation and ranging. It is a system that uses sound waves to calculate the distance to an object.
Answers to Exploring the Ocean
1.
2.
3.
4.
5.
6.
7.
8.
9.
Darkness, cold, and extreme pressure Sound navigation and ranging, is a system that uses sound waves to calculate the distance to an object Mid-ocean ridge – a continuous range of mountains that winds around Earth Trench – a steep sided canyon in the deep ocean floor Continental slope – an incline at the edge of a continental shelf Abyssal plain – the smooth, nearly flat region of the ocean floor Seamount – a mountain that is completely under water Continental shelf – a gently sloping, shallow area of the ocean floor that extends outward from the edge of a continent Volcanic island – the peak of a volcano that beaks the ocean surface
Quick Check
A smooth, nearly flat region of the ocean floor is call a(n) A. trench.
B. mid-ocean ridge.
C. abyssal plain.
D. sea mount.
Quick Check
Which ocean floor feature makes up the deepest parts of the ocean?
A. abyssal plain B. mid-ocean ridge.
C. deep-sea trench.
D. sea mount
Quick Check
What three (3) factors make ocean floor research difficult?
1.
2.
3.
_______ ______ ______
Quick Check
What are some features of the ocean floor?
1.
2.
3.
4.
5.
6.
__________ __________ __________ __________ __________ __________
Lesson 12
Waves, Currents, and Tides
EQ: What causes the ocean to move?
Waves
• A wave is a disturbance that transfers energy through matter or space.
• Wind transfers energy into the sea causing waves to occur.
• Undersea earthquakes and landslides can also put energy into the water to produce ocean waves.
Waves
• The size of a wave depends on the amount of energy that is transferred to the water.
• The amount of energy transferred depends on three things: – Wind speed – Length of time it blows – Distance over which it blows • As each of these factors increase, so does the size of the wave.
Ocean Currents
• Winds are responsible for ocean currents.
• A surface current is an ocean current that moves along the top part of an ocean.
• Surface currents are moved by prevailing winds .
• Prevailing winds are winds that blow in regular directions almost all the time.
Ocean Currents
• Surface currents can be cold or warm.
• Those that flow from the poles toward the equator are cold.
• Those that flow from the equator towards the poles is warm.
• The Gulf Stream is a warm current that flows northward up the east coast of the United States toward Great Britain and western Europe.
Tides
• A tide is the rise and fall of the ocean’s surface caused mostly by the gravitational pull of the moon .
• At high tide, the ocean water has risen as high as it will go on a shore.
• At low tide, the ocean water has fallen as low as it can go on a shore.
Tides
• Earth’s rotation on its axis affects which tides will occur at a certain place on Earth.
• High tides occur about every 12 hrs .
• Low tides occur about every 12 hours .
• The time between low tide and high tide is about 6 hrs.
Quick Check
What causes tides but NOY waves and currents?
A. winds and the moon’s gravity B. mostly the moon’s gravity C. mostly the sun’s gravity D. only winds
Quick Check
What is the main cause of the Gulf Stream?
A. storms B. winds that blow now and then C. winds that blow in regular directions D. the moon’s gravity
Quick Check
If the first high tide of the day occurs at 1:00 a.m., the next high tide will come closest to A. 7:00 a.m.
B. 7:00 p.m.
C. 1:00 a.m. the next day D. 1:00 p.m.
Quick Check
What is the cause waves and currents but NOT tides?
A. wind B. the moon’s gravity C. the sun’s gravity D. Earth’s gravity
Quick Check What is the cause of most ocean waves?
A.
B.
C.
D.
The climate The large ships in the ocean The moon The wind
Quick Check
A wave will increase in height when the distance over which the wind blows over the sea A. increases.
B. decreases.
C. stays the same.
D is 0 kilometers.
Quick Check
The wave will increase in height when the speed of the wind A. remains unchanged for a long time.
B. decreases.
C. increases.
D. changes direction.
Quick Check
Which will produce the highest wave?
A. wind speed of 10 km/h B. wind speed of 20 km/h C. wind speed of 30 km/h D. wind speed of 40 km/h
Quick Check
Which unit of measurement would you use to express the area of the Atlantic Ocean?
A. m B. km C. m² D. km²
Section 13 – 1
Wave Action
Wave Action
How does a wave form?
How does wavelength and wave height change as a wave enters shallow water?
How do water particles move within a wave?
How Waves Form
• Most waves form when winds blowing across the water’s surface transmit their energy to the water. • Near shore, the wave height increases and the wavelength decreases.
• As the energy in a wave passes, water particles move in a circular path, ending in their original position.
Describing Waves
• • • • • Crest – highest part of a wave Trough – lowest part of a wave Wavelength – horizontal distance between crests or troughs Wave height – vertical distance from the crest to the trough Frequency – number of waves that pass a point in a certain amount of time
How Waves Change Near Shore
• • • In deep waters, waves travel as long, low waves called swells.
Near shore, the wave height increases and the wavelength decreases.
When the wave reaches a certain height, the crest of the wave topples. The wave breaks onto the shore, forming surf.
How Waves Affect the Shore
• • •
Longshore Drift
along the beach – movement of sand
Rip Currents
rapidly back to sea through a narrow opening – a rush of water that flows
Sandbar
–as waves slow down, they deposit the sand they are carrying on the shallow, underwater slope in a long ridge
Reducing Beach Erosion
• • • • Over time, erosion can wear away a beach Threatens homes, buildings, property
groin
– a wall of rocks or concrete to reduce erosion along a stretch of beach Building groins can increases the amount of erosion father down the beach
Answers to Wave Action
1.
2.
3.
4.
5.
6.
7.
Crest Wavelength Trough Wave height The waves height increases and its wavelength decreases When the waves come into the shore at an angle, resulting in a movement of sand along the beach Build a groin 8. Wave – the movement of energy through water (b) 9. Frequency – the number of waves that pass a point in a given amount of time (d) 10. Longshore drift – the movement of sand down a beach (a) 11. Sandbar – a long, low ridge of sand deposited offshore as waves go back out to sea © 12. Rip current – a rush of water that flows out from the shore through a narrow opening (f) 13. Groin – a wall of rocks or concrete built outward from a beach to prevent erosion (e)
Quick Check What is the cause of most ocean waves?
A.
B.
C.
D.
The climate The large ships in the ocean The moon The wind
Quick Check
Rolling waves with a large distance between crests have a long A.
B.
C.
D.
wave height wavelength frequency trough
Quick Check
Groins are built to reduce the effect of A.
B.
C.
D.
tsunamis.
longshore drift.
rip currents.
deep currents.
Quick Check
Sand is gradually carried down the beach by A.
B.
C.
D.
groins sandbars crests longshore drift
Section 13 - 4
Currents and Climate
EQ: What forces cause surface currents and deep currents?
Surface Currents
• • •
Surface currents
basins.
are driven mainly by winds and follow global wind patterns, moving in circular patterns in ocean Surface currents affect water to a depth of several hundred meters.
Coriolis effect
currents - the effect of Earth’s rotation on the direction of winds and
How Surface Currents Affect Climate
• • • • A surface current warms or cools the air above it, influencing the climate of the land near the coast.
Climate is the pattern of temperature and precipitation typical of an area over a long period of time.
Currents affect climate by moving cold and warm water around the globe.
Currents are large streams of moving water that flow through the oceans
Deep Currents
• • • •
Deep currents
are caused by differences in density rather than surface winds.
Cold waters at the bottom of the ocean creep slowly across the ocean floor.
Deep currents move and mix water around the world.
They move much slower than surface currents.
Upwelling
• • • Upwelling is the upward movement of cold water from the ocean depths.
As wind blows away the warm surface water, cold water rises to replace it.
Upwelling brings up tiny ocean organisms, minerals, and other nutrients from the deeper layers of the water.
El Niño
• • •
El Ni ñ
Ocean.
o
- an abnormal climate event that occurs every 2 to 7 years in the Pacific This causes a sheet of warm water to move eastward toward the South American coast.
El Niño can last for one to two years before the usual winds and currents return.
Answers to Currents and Climate
1.
2.
3.
4.
5.
Surface Warm of cold Differences in density Cold By moving warm or cold water around the globe, warming or cooling the air above
6. Upwelling increases the supply of nutrients by bringing up tiny ocean organisms, minerals and other materials from the deeper layers of the water 7. Currents 8.
9.
Coriolis effect Climate 10. El Niño
Quick Check
Winds and currents move in curved paths because of A. the Coriolis effect.
B. longshore drift.
C. wave height.
D. tides.
Quick Check
Currents are caused by A. gravitational pull of the moon.
B. gravitational pull of the sun.
C. Winds, the earth’s rotation, and differences in water density.
D. the earth’s rotation.
Quick Check
What causes tides but NOT waves and currents?
A. winds and the moon’s gravity B. mostly the moon’s gravity C. mostly the sun’s gravity D. only winds
Quick Check
What is the MAIN cause of the Gulf Stream?
A. storms B. winds that blow now and then C. winds that blow in regular directions D. the moon’s gravity
Section 13 - 2
Tides
EQ: What causes tides?
Tides
What causes tides?
How can tides be used to generate electricity?
Describe the positions of the sun and the moon, in relation to Earth when spring tides occur.
What causes tides?
• • • • • Tides are caused by the interaction of Earth, the moon, and the sun.
The moon pulls on the water on the side closest to it more strongly than it pulls on the center of the Earth.
This pull creates a bulge of water, called a tidal bulge, on the side of Earth facing the moon.
The water opposite the moon is pulled toward the moon less strongly than the water facing the moon.
This water is “left behind,” forming a second bulge.
The Daily Tide Cycle
• • As Earth turns completely around once each day, people on or near the shore observe the rise and fall of the tides as they reach the area of each tidal bulge.
The high tides occur about 12 hrs. and 25 mins. Apart in each location.
The Monthly Tide Cycle
• • • • • • Changes in the positions of Earth, the moon, and the sun affect the height of the tides during a month.
Twice a month, at he new moon and the full moon, the sun and moon are in a straight line.
Their combined gravitational pull produces the greatest range between high and low tide, called a spring tide.
In between spring tides, at the first and third quarters of the month, the sun and moon pull at right angles to each other, producing a neap tide.
A neap tide is a tide with the least difference between low and high tide.
The movement of large amounts of water between high and low tide are a source of potential energy—energy that is stored and waiting to be used.
Answers to Tides
1.
2.
3.
4.
5.
6.
A and D C or E Spring Lower Spring Greater 7. Neap tide – tide with the least difference between high and low tide © 8. High tide – tide in which water reaches its highest point on the beach each day (d) 9. Spring tide – tide with the greatest difference between high and low tide (a) 10. Low tide – tide in which water reaches its lowest point on the beach each day (b)
Quick Check
At the full moon, the combined gravitational pulls of the sun and the moon produce a A. surface current.
B. neap tide.
C. spring tide.
D. rip current.
Quick Check
A tide which water reaches its lowest point on the beach each day is called A. neap tide.
B. high tide.
C. spring tide.
D. low tide.
Quick Check
Tide with the least difference between high and low tide is called A. neap tide.
B. high tide.
C. spring tide.
D. low tide.
Quick Check
A tide in which water reaches its highest point on the beach each day is called a A. neap tide.
B. high tide.
C. spring tide.
D. low tide.
Quick Check
If the first high tide of the day occurs at 1:00 am, the next high tide will come closest to A. 7:00 am B. 1:00 am the next day C. 7:00 pm D. 1:00 pm
Quick Check
Tide with the greatest difference between high and low tide is called a A. neap tide.
B. high tide.
C. spring tide.
D. low tide.
Quick Check
High tides occur A. once every two days.
B. once a day.
C. twice a day.
D. four times a day.