Share with Your Students Name

Date

Vocabulary

STUDENT RESOURCE 1.1 INFORMATION SHEET

atmosphere the blanket of air that surrounds Earth Weather occurs in the layer of the atmosphere closest to Earth, called the troposphere. condensation the process by which a gas changes to a liquid Water vapor condenses when it is cooled. evaporation the process by which a liquid changes to a gas Warmer temperatures increase the rate of evaporation.

water vapor water in a gas state Water vapor is invisible. Air contains varying amounts of water vapor. weather the condition of the atmosphere at a given place and time Weather patterns form due to the uneven heating of Earth’s curved surface by the Sun.

Copyright © Houghton Mifflin Company. All Rights Reserved.

precipitation water that falls to Earth’s surface Precipitation occurs when water falls from clouds as rain, hail, sleet, or snow.

water cycle the continuous movement of water in the environment through evaporation, condensation, and precipitation The Sun is the “engine” that drives the water cycle.

WEATHER AND WATER • SECTION 1 WHAT IS THE WEATHER? • 9

What Causes Weather? 1. Make copies of Student Resource 1.1, Vocabulary, and distribute to students. Discuss the definitions with students as the terms come up throughout the section. 2. Have students brainstorm types of weather. Write the list on the board. Then ask: What is weather? (the condition of the atmosphere in a given place at a given time) Ask: Where does weather occur? Let students share their ideas, then explain that weather occurs in the lowest and densest layer of the atmosphere called the troposphere. The troposphere is between 10 and 20 km thick. This may sound like a lot, but it is actually a very thin layer compared to Earth’s size. 3. Now ask: What causes weather? (Let students share ideas.) Explain that weather results from the interaction of air, water, and the Sun’s energy. Because of Earth’s spherical shape, the Sun heats some parts of Earth more than others. This uneven heating sets air in motion and causes water to change state.

Student Resource 1.1 (p. 9)

The Water Cycle 20 minutes

Teacher Demonstration

Objectives • Students observe models of evaporation, condensation, and precipitation. • Students compare observed models to the water cycle. Materials For the teacher

Safety This activity requires students to observe a hot pot of boiling water. Caution students not to touch the hot pot or put their hands near or in the steam or boiling water. Unplug the pot before Step 1.

4 • EXPERIENCE SCIENCE

1

hot pot

4

*ice cubes

1

pie pan

Inquiry Focus • Observe

0.7 L *water (about 3 c) *Not provided in kit In Advance Begin boiling 0.7 L (about 3 c) of water before the activity so that the water level will have dropped noticeably.

The Water Cycle (continued)

Teaching Tip Step 1: Tell students that Earth’s atmosphere is made of 78% nitrogen and 20% oxygen; the remaining 2% is a mix of carbon dioxide, helium, neon, ozone, and water vapor. Make a pie chart of these percentages on the board.

1. Students observe water evaporate. Have students compare the current water level with the starting level in the pot. Ask: Where did the water go? (Some of it evaporated, becoming an invisible gas called water vapor.) 2. Students observe condensation in the air. Next, have students look above the pot of water. Ask: What is steam? (Accept all answers.) Explain that when water vapor contacts cooler air, it condenses, or turns back into a liquid. The term steam is commonly used to describe a cloud of condensed water vapor over a hot liquid. However, sometimes the term steam is used as a synonym for water vapor. 3. Students observe condensation on a surface. Resume boiling the water. Put ice cubes in the pie pan and hold it above the steam. Have students observe the condensation on the pan’s bottom. Ask: Where did the drops come from? (They are condensed water vapor.) 4.Students observe precipitation. Hold the pan in place until water drips from the bottom. If necessary, tilt the pan slightly. Ask: Where did the drips come from? (the pan) Tell students that these drips formed like raindrops. Small drops of water combined into larger ones. When the drops became heavy enough, they fell. Tell students that water in the atmosphere that condenses and falls to Earth is called precipitation.

A The experiment setup

5. Students relate their observations to the water cycle. On the board, write condensation, precipitation, and evaporation as shown in the diagram. Connect the terms with arrows to create a circular pattern. Ask: What is this three-step process? (the water cycle) Tell students that water constantly cycles in and out of the atmosphere. Water enters the atmosphere through evaporation from Earth’s surface. The water vapor condenses in cold air, becoming clouds. There, tiny droplets combine to form larger droplets. When heavy enough, the droplets fall as precipitation. The water cycle is at the heart of weather.

Condensation

Precipitation

Evaporation

Assessment Have a student sketch the water cycle on the board. Discuss as a class where to put the labels evaporation, condensation, and precipitation.

A The water cycle SECTION 1 WHAT IS THE WEATHER? • 5

Name

What Is the Weather Today?

Date STUDENT RESOURCE 1.2 INFORMATION SHEET

Weather Symbols

Wind Speed

Precipitation

Cloud Cover Percentage

Symbol

Type

Symbol

0%

Liquid; drops about 1 mm in diameter

Drizzle

10%

Notes

Speed in mph

Symbol

20 minutes, followed by brief temperature readings each day for three weeks

calm 1–4

20%–30%

5–8

Fog

40% 50%

9–14

60%–70%

Solid; chunks or balls of ice 5 mm to 75 mm in diameter

Hail

80%

15–20 21–25

90%

Haze

Objectives • Students measure air temperature (ºC and ºF) using a thermometer.

26–31

100%

Liquid; drops 1 mm to 3 mm in diameter

Rain Weather Fronts

38–43 44–49

Symbol

Shower

Cold front

32–37

• Students record data of daily weather conditions, using weather symbols.

50–54 Solid; pellets of ice 35 mm or less in diameter

Warm front

Sleet Stationary front

55–60 61–66 67–71

Occluded front

Smoke

Air Pressure High pressure Low pressure

72–77 Solid; six-sided ice crystal about 0.1 mm in diameter

Snow

H L

Wind Direction N NW

NE

SW

SE

Thunderstorm W

E

Falling pressure

Hurricane Rising pressure

S Example: West wind 5–8 mph

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Type

Pairs

Materials For each pair

Student Resources • 1.2 Weather Symbols

1

• 1.3 Using a Thermometer

thermometer

For the teacher

• 1.4 My Weather Chart

1

*local weather forecast (from newspaper)

Inquiry Focus • Record Data

1

*marker, erasable red

10 • WEATHER AND WATER • SECTION 1 WHAT IS THE WEATHER?

66027.SEC04pg009_013.Indd 10

9/17/05 3:51:36 PM

*Not provided in kit

Student Resource 1.2 (p. 10)

cold front

1. Students discuss weather variables. Tell students that a variable is a factor that can change. Ask: What weather variables do meteorologists include in their weather reports? (temperature; precipitation; wind speed and direction; cloud cover; air pressure; the location and movement of fronts)

drizzle

warm front

rain

winds from the northeast at 21–25 mph

snow 50% cloud cover

A Some common meteorological symbols

6 • EXPERIENCE SCIENCE

2. Students learn weather symbols. Make and distribute copies of Student Resources 1.2, Weather Symbols, and 1.4, My Weather Chart. Review the weather symbols. Tell students that they will make daily weather observations for three weeks and record their data in a chart. At first, they will record only cloud cover, precipitation, and temperature in degrees Fahrenheit. (Tell students that almost all countries use the Celsius scale but that air temperature in the United States is reported in Fahrenheit.)

What Is the Weather Today? (continued)

Safety Step 3: Caution students to handle the thermometers carefully.

3. Students review how to use a thermometer. Project the transparency of Student Resource 1.3, Using a Thermometer. Use the red pen to color in the thermometer tube on the transparency. Review how to read the thermometer and discuss the two scales, Fahrenheit and Celsius. Name a temperature in one scale, and have students tell the corresponding temperature in the other scale. Distribute one thermometer to each pair of students. Then have students measure the room temperature. (Note: temperature readings may vary.)

Name

Date

Name

Using a Thermometer

STUDENT RESOURCE 1.3 ACTIVITY SHEET

My Weather Chart

˚F

˚C

230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0

110

Date STUDENT RESOURCE 1.4 ACTIVITY SHEET

100 90 80 70 60 50 40 30 20 10 Copyright © Houghton Mifflin Company. All Rights Reserved.

0 –10

WEATHER AND WATER • SECTION 1 WHAT IS THE WEATHER? • 11

Student Resource 1.3 (p. 11)

Front (type)

Air Pressure (in inches, rising or falling )

Wind (direction and speed)

Type of Clouds

Dew Point (ºC/ºF)

Relative Humidity (%)

Precipitation (type)

Cloud Cover (%)

Practice reading the thermometer by coloring its tube to different levels, then reading in ºF and ºC.

Temperature (ºC/ºF)

–20

Date

Copyright © Houghton Mifflin Company. All Rights Reserved.

4.Students record the outdoor temperature. Have the class dress appropriately, collect their thermometers and handouts, then escort them outdoors. Check that students accurately use the thermometer as they measure air temperature in sunlight and shade. Tell students that meteorologists report air temperature measured in the shade. Have students compare their readings and record the shade temperature only (ºC and ºF) on the My Weather Chart Resource page.

12 • WEATHER AND WATER • SECTION 1 WHAT IS THE WEATHER?

Student Resource 1.4 (p. 12) SECTION 1 WHAT IS THE WEATHER? • 7

What Is the Weather Today? (continued) 5. Students record cloud cover and precipitation. Ask students to record the cloud cover percentage and any precipitation. Prompt students to use the symbols on the Weather Symbols Resource page.

Teaching Tip

6. Students compare their observations with today’s weather forecast. Read aloud the day’s weather forecast. Ask: Was the forecast accurate? (depends on the weather) Ask: What factors can make it hard to predict the weather? (changes during the day in wind speed and direction, temperature, cloud cover, and the speed or direction of weather fronts) Tell students to save the My Weather Chart Resource page. They will use it to record daily observations.

Step 6: You may wish to store or post students’ My Weather Chart Resource pages in a common area to make sure they are available for later Investigates.

Assessment Have students look at their thermometers. Ask: Which temperature is warmer: 50ºC or 100ºF? (50ºC)

Section Assessment Name

Date

Section 1 Assessment

STUDENT RESOURCE 1.5 ASSESSMENT SHEET

Materials For each station

Vocabulary Write the term that completes each sentence. Some terms have more than one word.

1 Water in the gas state is called water vapor

.

2 The blanket of air that surrounds Earth is called its

atmosphere

.

The Water Cycle

3 Complete the chart by labeling

2

cups, plastic

2

thermometers

•

*water, cold and warm

•

*ice

Student Resource • 1.5 Section 1 Assessment

*Not provided in kit

the steps in the water cycle. Condensation

1. Set up enough stations so that one-third of the class can work independently on the hands-on portion of the assessment at a time. At each station, place a plastic cup of cold water labeled A, a plastic cup of warm water labeled B, and two thermometers. Add warm water and ice as needed between rotations.

Copyright © Houghton Mifflin Company. All Rights Reserved.

Precipitation

Evaporation

Reading a Thermometer

4 Read the thermometers. Record the temperature of the water in each cup, in °F and in °C. Cup A:

Cup B:

Answers depend on water in the cups.

5 Which cup will lose water to evaporation more quickly? Explain the reason for your answer.

Cup B will evaporate more quickly because it is a higher temperature (or because it is warmer).

WEATHER AND WATER • SECTION 1 WHAT IS THE WEATHER? • 13

66027.SEC04pg009_013.Indd 13

Student Resource 1.5 (p. 13)

9/14/05 9:54:53 PM

2. Make copies of the Section 1 Assessment Student Resource and distribute to students. Divide the class into three groups. While one group works at the stations to complete the hands-on portion of the assessment, the other two groups may complete the top of the Resource page. Rotate the groups until each student has completed all three sections of the assessment. 3. Discuss the answers as a whole-class activity.

8 • EXPERIENCE SCIENCE