weather unit investigation i: locating matter lesson 1: weather or not lesson 2: raindrops keep...

Weather Unit

Investigation I: Locating MatterLesson 1: Weather or NotLesson 2: Raindrops Keep Falling . . .Lesson 3: Having a Melt DownLesson 4: It’s SublimeLesson 5: Water World

Weather Unit – Investigation I

Lesson 1:

Weather or Not

Unit 3 • Investigation I

© 2004 Key Curriculum Press.

ChemCatalyst

Below are a picture and weather report

of a hurricane off the coast of Florida in

the United States.

(cont.)



(cont.)

FORECAST FOR THE MIAMI AREA: The

tenth depression of the season in the Atlantic

has become Hurricane Jan. The center of

Jan is southeast of Florida. The maximum

sustained winds are near 120 miles per hour.

The estimated minimum central pressure is

28.5 inches. Skies over Miami are mostly

cloudy. The temperature is 35C / 95F with

90% humidity. (cont.)



(cont.)

Jan is expected to drop as much as 10

inches of rain in the southern part of Florida

with rising temperature and humidity.

• What are hurricanes and what do you

think causes them?

• What is weather? What causes weather?

• How do meteorologists predict things like

hurricanes?



The Big Question

• What causes water to ‘cycle’ or move around on the planet?



You will be able to:

• Explain what causes rain on the planet Earth.



Activity

Purpose: In this activity you will heat and cool water in a flask with a balloon attached. Your observations will help you determine what makes the water “cycle.”

(cont.)



Materials: (for each team of two students)

250 mL Erlenmeyer flask

25 mL graduated cylinder

Medium sized party balloon

5 mL of water

Hot plate

Oven mitt

Bucket or large beaker with ice and water

(cont.)



Making Sense

• Based on this experiment, explain what causes water to “cycle” around the planet?



Notes• Evaporation is the changing of a substance from

the liquid phase to the gas phase. Condensation is the changing of a substance from the gas phase to the liquid phase.

• Gas, liquid, and solid are three different phases of matter. A phase change refers to the conversion of a liquid to a gas or a solid, or vice versa.

• A physical change is one in which the form or temperature of a substance is changed without changing its chemical make-up.

(cont.)



• Humidity is a measure of the amount of water vapor (or gaseous water) in the air.

Notes (cont.)



Check-In

Answer the following question:

• Using what you learned today about

the movement of water, explain what

causes rain on the planet Earth.



Wrap-Up

• Weather is an interaction between the sun (a heat source), the water on the planet, the Earth’s surface, and the Earth’s atmosphere.

• Water moves around through phase changes.

• Phase changes affect the volume of substances.


Lesson 2:

Raindrops Keep

Falling . . .



ChemCatalyst Annual rainfall in the United States

(cont.)



(cont.)

• How much rain fell where you live?

• How is rainfall measured?

• What type of instrument or container is used to measure rainfall?



The Big Question

• How do meteorologists keep track of rainfall?




• Relate volume of water to rainfall amount.



Activity

Purpose: This lesson introduces you to precision in measurement and allows you to explore measuring rainfall in inches and milliliters.

(cont.)



Materials: (per team of 2 students)


100 mL beaker

12 inch ruler

Water bottles (use plastic pipettes or droppers if you do not have water bottles)

(cont.)



Making Sense

Meteorologists can keep track of the amount of rainfall by measuring either the volume or the height of rainfall in a rain gauge. • If the amount of rainfall increases, do

both the volume and height of water in the rain gauge keep track of this increase? Explain your thinking.

(cont.)



(cont.)

• What does the precision of measuring height and volume depend on? Is there a difference in the precision of measuring height or volume? Explain your thinking.

(cont.)



Volume vs. Height of Water

0

5

10

15

20

25

0 0.5 1 1.5 2 2.5 3 3.5 4

Height (inches)

Volume (mL)

0 1/ 2 1 1 1/2 2 2 1/ 2 3 3 1/2 4

(cont.)



• Significant figures are the numbers one can read off of an instrument or piece of equipment, plus one more estimated number. The glassware or instrument being used in a measurement determines how many significant figures can be recorded.

55

50

Notes

(cont.)



Significant FiguresGlassware # of

decimal places

reading: 10 ml of

liquid

number of significant

figs

Beaker 0 10 mL 2

Erlenmeyer Flask

0 10 mL 2

Graduated Cylinder

1 10.0 mL 3

Graduated Pipette

2 10.00 mL 4

Notes (cont.)

(cont.)



Measuring Rainfall Data

Height (inches)

0 in 7/8 in 1 7/8 in 2 7/8 in 3 7/8 in

Volume (milliliters

)

0 mL 5 mL 10.0 mL

15.0 mL

20.0 mL

Notes (cont.)

(cont.)



Notes (cont.)

• Two quantities are proportional if a graph of the two variables results in a straight line that passes through the origin (0, 0).

(cont.)



Volume vs. Height of Water

0

5

10

15

20

25

0 0.5 1 1.5 2 2.5 3 3.5 4

Height (inches)

Volume (mL)

0 1/ 2 1 1 1/2 2 2 1/ 2 3 3 1/2 40 1/2 1 1 1/2 2 2 1/2 3 3 1/2 4

Notes (cont.)



Check-In

Answer the following question:

• Suppose you find that 1.0 inch of rainfall in a graduated cylinder has a volume of 4.0 mL. What volume would you measure for 2.0 inches of rainfall?

A) 4 mL B) 4.0 mL C) 4.00 mLD) 8 mL E) 8.0 mL F) 8.00 mL

Explain your thinking.



Wrap-Up

• Precision differences in measurements are a result of the glassware or instrument that is used.

• Significant figures are defined as all of the numbers that can be read directly from an instrument, plus one estimated number.

(cont.)



(cont.)

• The volume of water in a cylindrical container is directly proportional to the height of the water.

• Graphs of two variables that are proportional always lead to a straight line through the origin.


Lesson 3:

Having a Melt Down



ChemCatalyst

• Meteorologists measure the snowpack in the mountains to predict the amount of water that will fill the lakes and reservoirs. Do you think that 3 milliliters of snow is the same as 3 milliliters of rain? Explain your reasoning.



The Big Question

• How can you convert from volume of snowfall to volume of liquid water?




• Understand the relationship between density, mass and volume.



• The density of a substance is the slope of the line for a graph of mass vs. volume.

Density = Mass/Volume

Notes

(cont.)



• The slope of a line is the change in y divided by the change in x.

• For a line that goes through the origin (0, 0), the slope is simply any value of y divided by the corresponding value of x.

Notes (cont.)

(cont.)



Slope = DensityMass vs. Volume of Snow

0

20

40

60

80

100

0 20 40 60 80 100

Volume (mL)

Mass (g)

Notes (cont.)



Activity

Purpose: This activity allows you to relate volume of snowfall with volume of rainfall by using the density of snowfall and rainfall.

(cont.)



Materials: (for each team of four students)


Scale

Water bottle (small dropper or plastic pipette if water bottles are not available)

(cont.)

(cont.)



Measured Calculated

Mass of water plus graduated cylinder (g)

Mass of water (g)

Volume of water (mL)

Mass/volume (g/mL)

Mass of the graduated cylinder empty: ______

(cont.)



Making Sense

• Explain how you can relate volume of snow to volume of rain.

(cont.)



Mass vs. Volume of Water

0

5

10

15

20

25

0 5 10 15 20 25

Volume (mL)

Mass (g)

water

snow

ice

(cont.)

(cont.)



m1 / V1 = slope = m2 / V2

(cont.)

(cont.)



Example Problem I: Imagine you have a box that is 5.0 mL in volume. What mass of ice will just fit this box?

Proportional Analysis

0.92 g = _ x __

1 mL 5.0 mL

x = (0.92)(5.0) = 4.6 g

Dimensional Analysis

5.0 mL 0.92 g = 4.6 g

1 mL

(cont.)

(cont.)



Example Problem II:You have 20 grams of snow with a density of 0.50 g/mL. What volume does this snow occupy (how many milliliters)?

Proportional Analysis

0.5 g = 20 g

1 mL x mL

x = (20) = 40 mL

Dimensional Analysis

20 g 1 mL = 40 mL

0.5 g

€

10.5

⎛

⎝ ⎜

⎞

⎠ ⎟

(cont.)



Example Problem III:

If you have 100 mL of snow, what volume of water do you have? (You must first find out what mass of snow you have and then convert that to volume of water.)

(cont.)

(cont.)



Step 1: Proportional Analsysis

0.5 g = x g

1 mL 100 mL

x = (0.5)(100 mL) = 50 grams

Step 2: Proportional Analsysis

1 g = 50 g

1 mL x mL

x = (1)(50) = 50 mL

(cont.)



Step 1: Dimensional Analysis

100 mL 0.5 g = 50 grams

1 mL

Step 2: Dimensional Analysis

50 mL 1 g = 50 mL

1 mL

(cont.)



Check-In

• You have equal masses of snow and

rain. Which has a greater volume?


• What is the mass of 14 mL of

rainwater?



Wrap-Up

• Density is a measure of the mass of

a substance per unit of volume.

• If the ratio between two quantities is

constant then a graph of these two

quantities will be a line that passes

through the origin.

(cont.)



• Water can have different densities

depending on whether it is snow, ice or

liquid (rain).

• When a substance changes phase

(from solid to liquid to gas) it changes

density.

(cont.)


Lesson 4:

It’s Sublime



ChemCatalyst

• Describe the differences between the

two.

• Why do you think one is called “dry”

ice?



The Big Question

• How different are the densities of a solid and a gas of the same substance?




• Understand the change in density as a substance goes from a solid to a gas.



Activity

Materials:

5-20 grams of dry ice per team of students

Styrofoam cooler or ice chest

Scale

Medium plastic garbage bags—five-gallon

size

Twist tie(cont.)



2 Oven mitts

Five gallon bucket or other cylindrical

receptacle (Note: 5 gallons ~19 liters)

(cont.)

(cont.)



Mass of CO2(s) (g)

Volume of CO2 solid (mL)

Volume of CO2 gas (mL)

Copy this table into your notebook.

Note: This table is different than the one in your book.

(cont.)

(cont.)



Safety Note: Use gloves – dry ice can

cause frostbite.



Making Sense

• If you sublime 1 mL of CO2 (s), what volume will the gas occupy?

• How many times larger than the volume of the solid carbon dioxide is the volume of the carbon dioxide gas?

(cont.)



Mass vs. Volume of Gaseous Carbon Dioxide

0

20

40

60

80

100

0 20 40 60 80 100

Volume (mL)

Mass (g)

CO2 (s)1.56 g/mL

CO2 (g)0.0019 g/mL

(cont.)

(cont.)



Solid CO2 Gas Model A Gas Model B Gas Model C

€

→

Which model is correct?

(cont.)

(cont.)



How do we find the volume of the solid?

•D = m/V or V = m/D

• We know m = g (from our data table)

• D = 1.56 g/mL (from graph)

• So do the math . . .

(cont.)



Sample Data

Mass of CO2(s) (g)

Volume of CO2 solid (mL)

Volume of CO2 gas (mL)

5.0 g 2500 mL

8.2 g 4200 mL

12.7 g 6500 mL



Wrap-Up

• Sublimation occurs when a substance

goes directly from a solid phase to a

gas phase (or vice versa).

• The density of a gas is about 1/1000

the density of the same solid.


Lesson 5:

Water World



ChemCatalyst

Suppose a quantity of rainwater

occupies a volume of 1 mL.

• What volume do you think the

rainwater occupies as water vapor?


• When water changes phase what other

changes take place? Name at least

three changes.



The Big Question

• How are volume, density, and phase of water related to weather?




• Explain the increase in volume as 1 mL of water goes from a liquid to a gas.



Activity

Purpose: The purpose of this lesson is to explore how phase changes are related to volume changes, density changes, and the water cycle in general. Part I: Comparing densitiesDensities of various substances have been labeled in the Density Landscape handout. (cont.)



cloud

rainH2O (l), 1.00 g/mL

iceH2O (s), 0.92 g/mL

happy bear

carbon dioxide subliming from dry ice, CO2 (g), 0.0019 g/mL

iron anchorFe (s), 7.87 g/mL

mine shaft leading to gold, Au (s),

19.32 g/mL

oil0.92 g/mL

pine log 0.5 g/mL

helium blimp0.00016 g/mL

water vapor subliming from

snow, H2O (g), 0.0006 g/mL

aluminum coolerAl (s), 2.70 g/mL

dry ice to preserve fish

CO2 (s), 1.56 g/mL

fire extinguisher containing liquid carbon

dioxideCO2 (g), 1.2 g/mL

lakeH2O (l), 1.00 g/mL

snowH2O (s), 0.92

g/mLair at 3000 m above

sea level0.00091 g/mL

air at sea level0.0012 g/mL

molten lava2.2 g/mL

solid lava2.4 g/mL

(cont.)

(cont.)



Part II: Average rainfallA map of average rainfall in the United States (in inches/yr) is shown below.

(cont.)



Making Sense

• How are volume, density, and phase of water related to the weather?



Phase Change

• Drives the water cycle and weather

• Results in changes in volume and density

Notes



Check-In

As water moves around the water cycle,

its volume changes.

• If rainwater occupies a volume of 1

mL, what volume will it occupy when it

forms water vapor?

• What is the main reason for the

increase in volume during this phase

change?



Wrap-Up• The density of a substance in the solid phase

is nearly the same as its density in the liquid

phase.

• The density of a substance in the gaseous

phase will be much lower than its densities in

the liquid and solid phases. Gases are about

1000 times less dense than liquids and solids.

(cont.)



• The density of a substance has a great

deal to do with where that substance

can be found on the planet in

relationship to other substances.

(cont.)

weather unit investigation i: locating matter lesson 1: weather or not lesson 2: raindrops keep...

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