Fig. 11-CO, p. 297

Fig. 11-1a, p. 299

Fig. 11-1b, p. 299

Fig. 11-2a, p. 300

Fig. 11-2b, p. 300

Fig. 11-2c, p. 300

Fig. 11-2c, p. 300

Motion due to inertia

Combined effect

Motion due to gravity

c

Fig. 11-3, p. 300

Fig. 11-3, p. 300

1,650 km (1,023 mi)

Earth’s mass is 81 times the mass of the moon Moon

(81/82) r

(1/82) r Average Earth–moon distance (r)

Fig. 11-4, p. 300

Fig. 11-4, p. 300

Moon

Moon attracts ocean

Fig. 11-4, p. 300

Center of mass

Moon

Moon attracts ocean

Earth’s motion creates opposing bulge

Fig. 11-4, p. 300

Moon

Combined result

Fig. 11-5, p. 301

Fig. 11-5, p. 301

Inertia (sometimes called centrifugal “force”): The same for all particles in and on Earth.

Bulge opposite moon

Gravitational attraction: Decreases as the square of the distance from the moon.

4 1

CEMoon

Forces are balanced here

Bulge toward moon

3 2 Tractive forces: Net force when effects of inertia and gravitational attraction are combined. They create two bulges in the ocean: one in the direction of the moon, the other opposite.

The two forces that can move the ocean—inertia and gravitational attraction—are precisely equal in strength but opposite in direction, and thus balanced, only at the center of Earth (point CE ).

Fig. 11-6, p. 301

Fig. 11-6, p. 301

Water bulge resulting from inertia (centrifugal “force”)

North Pole

Moon

Water bulge resulting from gravitational attraction

South Pole

Fig. 11-7a, p. 302

Fig. 11-7a, p. 302

1226 (about noon), Island exposed

1838 (6:38 P.M.) Island submerged

0613 (6:13 A.M.) Island submerged

Moon

Inertia bulge Earth turns eastward

Gravity bulge

0000 (midnight), Island high and dry

North Pole

Fig. 11-7b, p. 302

Fig. 11-7b, p. 302

High tide

Average sea level

Low tide

0000 0613 1226 1838

Time of day

Fig. 11-8, p. 303

Fig. 11-8, p. 303

The moon moves this much in 8 hours . . .

. . . and this much in 24 hours

Moon

Earth

North x

PoleTidal

bulges

Noon 8:00 P.M. 4:00 A.M. Noon 12:50 P.M. on Day 2

8 hours 8 hours 8 hours 50 minStart 1 Solar

day1 Lunar

day

North x

Pole

North x

Pole

North x

Pole

North x

PoleRo

tati

on

Fig. 11-8, p. 303

The moon moves this much in 8 hours . . .

. . . and this much in 24 hours

North x

Pole

8:00 P.M.

8 hours

North x

Pole

12:50 P.M. on Day 2

50 min

1 Lunar day

Start

North x

Pole

Moon

Earth

Tidal bulges

Noon

Ro

tati

on

Stepped Art

North x

Pole

4:00 A.M.

8 hours

North x

Pole

Noon

1 Solar day

8 hours

Fig. 11-9, p. 303

Fig. 11-9, p. 303

N

Moon

S

Fig. 11-10, p. 303

Fig. 11-10, p. 303

Island partly submerged (lower high tide)

North Pole

Island submerged (higher high tide)

Moon

Island exposed (low tide)

Earth turns eastward

Equator

South Pole

Fig. 11-11a, p. 304

Fig. 11-11a, p. 304

Lunar tide Solar tide

SunFull moon

New moon

Spring tides Earth turns

Fig. 11-11b, p. 304

Fig. 11-11b, p. 304

First-quarter moon

Lunar tide

Solar tide

Earth turns Sun

Third-quarter moonNeap tides

Fig. 11-12, p. 305

Fig. 11-13, p. 306

Fig. 11-13, p. 306

Semidiurnal tidesDiurnal tidesMixed tides

d

(ft) Mixed tide, Los Angeles Diurnal tide, Mobile, Alabama Semidiurnal tide, Cape Cod (m)14 Higher high tide 410 Lower high tide 6 High tide 2

High tide 3

4 10 0

–4Low tide

–1

0 612 18 24 30 0 6 12 18 24 30 36 42 48 0 6 12 18 24 30 36 42 48 a Time (hr) b Time (hr) c Time (hr)

Lower low tide

Higher low tide Low tide

484236

Fig. 11-14, p. 307

Fig. 11-14, p. 307

N

AP

Tidal crest enters basin, trends toward right side (in Northern Hemisphere) due to Coriolis effect.AP = amphidromic point

a

Fig. 11-14, p. 307

High tide

b

AP = amphidromic point

N

AP

Rising tide

Low tide

Fig. 11-14, p. 307

High tide

Rising tide

AP

c

AP = amphidromic point

N

Falling tide

Fig. 11-14, p. 307

Falling tide

Low tide

High tide

d

AP = amphidromic point

N

Fig. 11-15, p. 308

Fig. 11-16a, p. 308

Fig. 11-16a, p. 308

6 hr

8 hr 4 hr

10 hr 2 hr

0 hr 0 hr

Open ocean

Fig. 11-16b, p. 308

Fig. 11-16b, p. 308

Québec

4 hr

6 hr 2 hr

6 hr Newfoundland4 hr

2 m

8 hr1 m

0 hr0 hr

New Brunswick

10 hrCape Breton

Island

Nova Scotia

0 100 200 km

Bay o

f Fundy

1 100 mi

Fig. 11-17a, p. 309

Fig. 11-17a, p. 309

Open ocean

2 hr 4 hr

Fig. 11-17b, p. 309

Fig. 11-17b, p. 309

New Brunswick

10 mSt. John

3.5 hr

10 m3 hr 7.5 m 4 hr

5 m 15 m4.5 hr

Nova Scotia

0 50 100 km

10 50 mi

Fig. 11-18a, p. 309

Fig. 11-18b, p. 309

Fig. 11-19, p. 311

Fig. 11-20, p. 312