Science 8 Unit 3: Water Mr. Birt

Name Class

Contents

1. Bill Nye - Water2. Properties of water3. Heat Capacity and Universal Solvent4. Water Cycle5. Drainage Basins6. Running Water and Erosion7. Flood Plains and Deltas

Name:

Class

Date

Bill Nye: The Water Cycle

Warm-up question: When water evaporates it turns into water vapor. How does

this happen if the water doesn't get hot enough to boil?

1. Fill in the boxes in the diagram.

2. What is the scientific name of the water cycle?

3. Why do some liquid water molecules evaporate into a gas?

4. What is the opposite of evaporation?

5. What two things are needed for condensation?

6. What is the chemical formula for water?

7. How does conserving electricity help protect water?

C^

/U-Vme

Module 3, Lesson 1 5

Vocabulary

• salt water

• universalsolvent

• freshwater

• density

• hydrometer

• buoyant force

• heat capacity

• Coriolis effect

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Q .7

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Lesson 1

Properties of Water

Learning Outcomes

After completing this lesson you will be able to

• explain why water is referred to as the universal solvent

• compare and contrast characteristics of freshwater and saltwater

• describe how the heat capacity of large bodies of water andthe movement of ocean currents influence climate

The Importance of Water

Water is an important substance that is needed for the

_of living organisms.2. . are dissolved in water and arethus able to enter cells. As you learned in Module 2,

aredissolved in water and removed from cells. Plants need water inorder to produce *. Through the utilization of water in

plants produce oxygen that is needed byanimals. Many types of plants and animals live and make their

6 in water. Humans use water to wash food, clothes, andeven themselves as a means of keeping clean and _,

. Fromthe smallest organism to the largest, water plays an importantpart in their -- „_,.^ •

Water shapes the lives of organisms and also shapes the eartharound us.'s. _ 47 _.water breaks rock up and ..,16 .,_.-waterwears rock down and transports sediments to other places.

Freshwater versus Salt Water

The earth's liquid water is categorized as either.

water orwater.

Oceans are examples of _, I .water. They cover. r1percent of theearth's surface. Salt water is water that has a high IT-level (high salt content). Salt water makes up approximately .16percent of the world's water.

It is because of water's ability to dissolve a large variety of/,

that the ocean is salty. As water flows down mountains

Module 3, Lesson 1

Grade 8 Science

and through fields, it dissolves ""63 - from the rocks andsediments it flows over. The J.. that is contained in the ocean isa collection of all the dissolved salt that has been transportedthere by rivers through the ages. Besides salt, ocean waterscontain vast amounts of other substances and. ZO .,....(forexample, copper, oxygen, nitrogen, sulphur). It is this ability todissolve a wide variety of solutes that allows water to be called a

a^--

Freshwater

Freshwater makes up 2-2 percent of the world's water. It hasrelatively? levels of dissolved salts within it. Freshwater is

found in 2 4 1 ^:,,r

and -

and

Rainwater and most water found in lakes is referred to as L`_water. Soft water has relatively low levels of disso l e d3 v

..&- water has higher levels of dissolved minerals andsubstances such as calcium carbonate, magnesium, or ferrousoxide. As water seeps into the ground, it. 2

substancesfound in the rocks and soil that make up the earth. Thesesubstances change the .ZL ;,of water, affect the. 'a `of soapsto cleanse and produce suds, cause

of mineral deposits inkettles and other appliances, and produce .coloured stainson surfaces exposed to water.

SCIENCE 8

Properties of Water - WORD BANK

Importance of Waterflowing

healthy

photosynthesisfood

homes

survivalfreezing

nutrients

wastes

Fresh versus Salt Watersalinity

solutessalt

universal solvent

Freshwaterability

ice

riversbuildup

lakes

rustdissolves

low

softgroundwater

minerals

tastehard

rainwater

9erceAts

C

freshminerals

'iV at c;r : He,a t Cu ac c

E' vel rsc 1

Aver

Cr/a s-s:

Date râ Heat Capacity

Provide students with the following graph. Indicate that 1.0 kaof substance A and 1.0 kg of substance B were placed in anoven set at 800°C.

Heat Capacity of Substances

1000 .-

800

0

v

E

200

0

2

4

6

8

10

Time (minutes)

Have students refer to the graph to answer the followingquestions in their science notebooks:

1. How long did it take for substance A to heat up to 800°C?How long did it take for substance B?

2. Which substance needed more heat energy to reach 800°C?

3. Which variables were controlled in this experiment?

4. The heat capacity of an object indicates how much heat

energy must be added to increase its temperature by 1°Celsius. If a substance has a large heat capacity, you must

add a large amount of heat to increase its temperature just a

little. You must also remove a large amount of heat to

decrease its temperature just a little. High heat capacity often

means a substance takes a long time to heat up or to cool

down.

Given this information, which substance has the higher heat

capacity?

(continued)

0

O

(continued)

5. Imagine you are at the beach on a very hot day. You walktoward the water. The sand is extremely hot. When you reachthe water, you find it is much cooler than the sand.

a. Using the term heat capacity, explain why the sand is hotand the water is cool.

b. Predict what the air temperature would be relative to thesand and water temperatures. Explain your thinking using

the term heat capacity..

â Universal Solvent

Provide students with the following:

1. We rely on the fact that water is a universal solvent(dissolves numerous substances) in our day-to-day lives.Identify some ways in which water is useful to us as auniversal solvent.

2. Sometimes we forget that water is able to dissolvesubstances. People add pollutants to soil, to the atmosphere,or to bodies of water without realizing the damage that couldbe done. Identify substances (all states of matter) that pollutewater because of its trait as a universal solvent.

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SCIENCE 8

The Water Cycle (Text p.331) Mr. Birt

1. Use the glossary at the back of the textbook to define the following terms:

a. condensation

b. evaporation

c. groundwater

d. precipitation

e. runoff

f. transpiration

2. Label the water cycle using p.331. (Include transpiration.)

3. What 2 sources of energy power the water cycle? (What 2 things supply the energy required?)

(1)

(2)

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DATE: NAIIAE: CLASS:

Drainage Basins (jO, 3ao)BLPA 10-9

Goal • Use this page to display your knowledge of drainage basins.

What to Do• Answer these two questions, then complete the map.

1. What is a drainage basin?

2. What is a drainage divide?

• On the map below colour and label five major drainage basins. Use a differentcolour for each basin. Draw and label the Continental Divide. tl Se- otrt auPo w

34ou)

the, 41 c osf of cl rla(A ctle mea4 ha sin

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:1

Copyright 0 McGraw -Hill Ryerson Limited. Permission to reproduce this page is granted to the purchaser for use in her/his classroom only. 445

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Module 3, Lesson 2

Grade 8 Science

Running Water and Erosion

How Does Running Water Cause Erosion?*

Weathering breaks down rocks, but weathering does not carryaway the pieces of rock. What carries the pieces away?

Another process moves the pieces of rock from one place toanother. It is called erosion. Erosion is the process by which piecesof weathered rocks are carried away.

Running water is the main force of erosion. Rivers, streams, andrunoff change the surface of the earth. Runoff is rainwater thatf lows over the earth's surface. During heavy rains there is a lot ofrunoff. As runoff flows over the earth's surface, it carries awaysoil pieces. Runoff empties into rivers and streams. The action ofrunning water has made more changes on the surface than anyother force.

Water in rivers and streams picks up pebbles, sand, silt, and clay.It even picks up heavier fragments, such as gravel, rocks, andboulders. All these things act as abrasives. They scrape away atthe bottoms and sides of streams.

Speed makes the difference. The faster a stream moves, the moreit carries. The more material the stream carries, the faster thebottom and sides of the stream are eroded. Streams flow veryfast when they go down steep slopes. Streams flow more slowlywhen they go down gentle slopes. Therefore, steep slopes areeroded faster than gentle slopes.

Sometimes streams carry extra water. That happens in times ofheavy rain. The extra water makes the stream move faster.Because it is faster, the water picks up more material and causesmore erosion.

Streams are the greatest source of erosion. They have worn awaylarge parts of our earth's surface.

* From Science Workshop Series Earth Science: Geology by Seymour Rosen©1992 by Globe Fearon, an imprint of Pearson Learning, a division ofPearson Education, Inc. Used by permission.

0Grade 8 Science Module 3, Lesson 2

21

Figure A

Water enters a stream in three ways.

1. Some rain falls directly into the stream.

2. Some runoff water flows off from the top of the ground.

3. Other water seeps in from under the ground.

A river system is made up of cne main stream and all thestreams that flow into it.

Questions: Studying Stream Erosion*

Stream A Stream B

* From Science Workshop Series Earth Science: Geology by Seymour Rosen©1992 by Globe Fearon, an imprint of Pearson Learning, a division ofPearson Education, Inc. Used by permission.

22

Module 3, Lesson 2

Grade 8 Science

0

Look at the diagrams on the previous page and answer the

following questions. Which stream ...

1. is moving down a gentle slope?

2. is moving down a steep slope?

3. is moving faster?

4. is moving slower?

5. carries more sediment?

6. carries less sediment?

7. erodes more?

8. erodes less?

Conclusions

1. Water flowing down a steep slope movesthan water flowing down a gentle slope.

(slower, faster)

2. Fast-moving water carries

sediment

than slow-moving water.

(more, less)

3. Fast-moving water erodes

than slow-

moving water.

(more, less)

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Grade 8 Science

Module 3, Lesson 2

23

CFill in the Blanks

Complete each statement using a term or terms from the list

below. Write your answers in the spaces provided. Some words

may be used more than once.

more

erode

faster

particles

breaks down

less

carried away

running water

downhill

1. Weathering only

rocks.

2. Erosion is the process by which pieces of rock are

3. The main force of erosion is

4. In times of heavy rain, sometimes streams carry

Streams carry all kinds of

6. Materials carried by streams

thesides and bottom of the stream.

01

7. Streams move only in a

direction.

8. Steep streams move

than gently

sloping streams.

9. Steep streams carry

particles than

gently sloping streams.

10. Gently sloping streams erode

than

steep streams.

Matching

Match each term in Column A with its description in Column B.

Write the correct letter in the space provided.

Column A

Column B

0

1. running water

2. runoff

3. erosion

4. steep slope

5. gentle slope

a) fast-moving stream

b) main force of erosion

c) slow-moving stream

d) carrying away ofweathered rock pieces

e) empties into rivers andstreams

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Module 3, Lesson 2 Grade 8 Science

What are Flood Plains and Deltas?*

Running water carries sediment. But it does not carry sediment

forever. Sooner or later, the sediment must settle. Some streams

may carry sediment very far. At some time, however, the

streams will deposit the sediment.

The sediment that streams deposit builds up two kinds of land

areas: flood plains and deltas.

Flood Plains

After a heavy rain, a stream carries more water than usual. This

raises the water level. Sometimes the level gets so high that the

water flows over its channel-the place it usually flows through.

Then there is flooding.

The flood water deposits fine sediment on the banks, which is

land next to the stream. Some st-re

r

builds up flat areas called flood plains. Soil on flood plains is

very good for farming.

Deltas

Almost every stream empties its water into a larger body of

water, which empties into a larger river or an ocean. The place

where a stream empties its water is called the mouth.

A stream flows slowly at the mouth. It deposits its sediment at

the mouth. The sediment builds large land areas, called deltas. A

delta is shaped like a triangle. It gets its name from the Greek

letter "delta" (A).

Large pebbles are deposited when a fast stream slows as it levels

out. This is called an alluvial deposit. Fast-flowing water has

more power than slow-moving water to carry heavy objects.

* From Science Workshop Series Earth Science: Geology by Seymour Rosen

©1992 by Globe Fearon, an imprint of Pearson Learning, a division of

Pearson Education, Inc. Used by permission.

Grade 8 Science Module 3, Lesson 2 25

Flood Plains and Deltas

Usually, stream water staysin the channel. It does notflow onto its banks.

Flood water deposits finesediment on both banks of astream. The sediment buildsflood plains.

In times of heavy rain,however, the water may flowover its channel.

26 Module 3, Lesson 2

Grade 8 Science

Questions: Flood Plains and Deltas

1. Flood plain soil is very fertile. There are many good farms on

flood plains. But the farmers are taking a big chance. Why?

2. Would you want to live on a flood plain?

3. Explain why or why not.

How a Delta Grows

Imagine yourself looking

down from high in the sky.

"a" is land

"b" is a stream

"c" is a large body of water

The stream empties intothe water.

The stream deposits its

sediment at its mouth.

The sediment builds up.

All the sediment is under

water.

Figure D

Grade 8 Science Module 3, Lesson 2 27

The sediment builds up andup. Much of it reaches abovethe water level. Much is noweven with the land. Thesediment is now "new" land.

The stream has cut newchannels across this newland.

How many new channels doyou see?

The buildup continues.More sediment is deposited.The land grows outward in

the shape of a delta. It willcontinue to grow.

Why will the delta keepgrowing?

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28 Module 3, Lesson 2

Questions: How a Delta Grows

Fill in the Blanks

Complete each statement using a term or terms from the listbelow. Write your answers in the spaces provided. Some wordsmay be used more than once.

deposited

deltas

erosion

slowlyflooding

mouth

flood plains

deltafarming

channel

1. The process by which parts of the earth's crust are carriedaway is called

2. Material that is eroded eventually is3. Soil on the flood plain is good for

the5. Stream sediment builds land areas called

and6. When water overflows its channel,

takes place.7. Fine sediment laid down during floods builds a

8. The place where a stream empties its water is called the

9. The water at the mouth of a stream usually flows

10. Sediment deposited at the mouth of a stream builds a

Matching

Match each term in Column A with its description in Column B.Write the correct letter in the space provided.

Column A

Column B

a) shape of a deltab) built by flood sedimentc) built at mouth of streamd) stream's ende) place a stream usually

flows through

Grade 8 Science

1. flood plain2. delta3. channel4. triangle5. mouth