Essential Question: What is the water cycle and how does it influence living things?

Warm-up: How does the majority of water get into the atmosphere? How does it get out of the atmosphere?

HW: No Homework

Energy in the Water Cycle

• About _____ Joules/gram are needed to change liquid water into vapor.

2260

• Fueled by SOLAR ENERGY through evaporation

Water Cycle (Hydrologic Cycle)• Model used to show the movement &

phase changes of water

Animated Water Cycle

Water Retention• Precipitation can

be stored or retained on land as ice & snow or on plants & trees

Infiltration (seep)• Gravity pulls water into the upper

parts of the Earth’s lithosphere – Subsurface Water

Poor Infiltration

Runoff• Water that flows over the land• 1/3 of water is returned to the water

cycle

Water Table• Interface between the zone of saturation

(filled with water) & the zone of aeration (partially filled with water)

Time in Months

Mill

imete

rs o

f W

ate

r

Time in Months

Mill

imete

rs o

f W

ate

r

Key = Need

= Supply

Wet Climate Dry Climate

Practice Questions

4

7Runoff

Evaporation

6Transpiration

5Condensation

1Precipitation

2Runoff

3Infiltration

8Ground Water Discharge

9Evaporation

10Evaporation

Essential Question: How does water move into and through the ground?

Warm-up:

In general, the probability of flooding decreases when there is an increase in the amount of

1) Runoff 2) Snow melt

3) Infiltration 4) Precipitation

Factors Affecting Infiltration

SLOPE of the LAND

- STEEPER the slope, the LESS the Infiltration

Less time to SEEP into GROUND

DEGREE of SATURATION

-More SATURATED the ground, the LESS infiltration

POROSITY –Amount of open space between particles

-GREATER the porosity the GREATER infiltration

3 factors that effect porosity are:

SHAPE

Well-rounded particles have

GREATER porosity

PACKING

More closely packed the particles, the lower the porosity

SORTING

-Material with well-sorted

particles has high Porosity

PERMEABILITY

-Ability of a material to allow fluid to pass through it

- Permeability = Greater Infiltration

CORK SPONGE

SHALE

CAPILLARITY

-Ability of water to RISE in small openings

-SMALLER the particle size, the

GREATER the capillarity

- Capillarity = Infiltration

VEGETATION Ground with

grasses, trees, & other plant types

have HIGH infiltration

LAND-USE

Impermeable surface like roads, parking lots, & buildings

decrease infiltration

Factors Affecting Runoff

• Rate of precipitation > Rate of Infiltration• Ground is 100% saturated

• Slope of surface to GREAT to allow infiltration

• Water is not evaporating fast enough

Which graph best describes the relationship between the slope of the land and the amount of surface runoff during a period of heavy rainfall?

Each tube was placed in a shallow pan of water. In which tube did the water rise the

highest?

1)A 3) C

2) B 4) D

When rain falls on a soil surface, flooding at that location would most likely occur if the

1) soil surface is permeable

2) soil surface is covered with vegetation

3) soil pore spaces are filled to capacity

4) infiltration rate exceeds the precipitation rate