Tides and Current

Question 1

Tide is

Answer 1

the vertical movement of water on the Earth’s surface

Question 2

Who and when determined gravity caused tides

Answer 2

Sir Issac Newton in 1687

Question 3

Flood current

Answer 3

The incoming tide along the coast and into the bays and estuaries

Question 4

When is the sun at its minimum declination? and what does that mean?

Answer 4

The sun is at it’s minimum declination during the vernal (March 21) and autumnal (September 23) equinoxes when it is directly over the equator.

Question 5

Aphelion

Answer 5

Earth is furthest from the sun, around July 2, the tidal ranges are below normal.

Question 6

Tides are very long period

Answer 6

waves that move through the oceans due to the forces exerted by the moon and sun

Question 7

Tides in narrow inlets and shallow water are

Answer 7

Disappated

Question 8

Spring tides occur _____.

Answer 8

When the Sun, Moon, and Earth are nearly in line

Question 9

What causes high tides?

Answer 9

The moon pulls the water most strongly below it on the earth, which is high tide. One the opposite side of the Earth, there is another bulge where the moon has the weakest gravity. These are the places where high tides occur. The weather spins through this, which causes tides in different areas https://scijinks.gov/tides/tides6.png.

Question 10

When the sun and moon are at right angles to each other, which type of tides occur?

Answer 10

Neap

Question 11

What causes low tides?

Answer 11

The moon pulls the Earth’s oceans towards it, creating a football shaped phenomena with bulges nearest to and furthest from the moon. The flat sides of the football are the areas of low tide, and the Earth spinning causes this to happen in different places.

Question 12

Where are the water bulges caused by extraterrestrial gravity on the Earth

Answer 12

One forms when the sun and moon are closest and the other where they are furthest apart. They stay alleged with the moon as the Earth rotates. The opposite to the moon bulge is due to inertia

Question 13

Spring tides

Answer 13

Sun and moon are in alignment, whether on the same side of opposite side. The high tides are the highest and the low tides are the lowest.

Question 14

Diurnal tide

Answer 14

Only one high tide and one low tide daily. In th eU.S., this is most common on the Gulf Coast.

Question 15

How many high waters usually occur each day on the East Coast of the United States?

Answer 15

Two

Question 16

Frequency of tides in the lunar day

Answer 16

most coastal areas in the U.S. have two high tides and two low tide every lunar day.

Question 17

Apogee

Answer 17

The moon is furthest from the Earth (about two weeks after Perigee) and tidal ranges are below average

Question 18

Ebb Current

Answer 18

the outgoing tide

Question 19

Mixed semidiurnal tide

Answer 19

the high tides and low tides differ in height. Most common on the West Coast

Question 20

Slack water

Answer 20

the period of time, usually brief, when there is no current flow near the time of high and low tide, prior to the change in direction

Question 21

The reference datum used in determining the heights of land features on most charts is _____.

Answer 21

mean high water

Question 22

Neap tides occur _____.

Answer 22

When the Sun and Moon are at right angles to each other

Question 23

Perihelion

Answer 23

The Earth is closet to the sun (jan 2) the tidal ranges are greater.

Question 24

A lunar day is how long?

Answer 24

A lunar day is 24 hours and 50 minutes because the moon revolves around the Earth in the same direction that the Earth rotates around it’s axis so it takes the Earth and extra 50 minutes to “catch up” to the moon.

Question 25

Funnel-shaped bays, like the Bay of Funny in Nova Scotia

Answer 25

can alter tides in this case increasing it to the highest tides in the world, over 15 meters.

Question 26

The strongest flood and ebb currents generally occur around

Answer 26

half-tide or halfway between high and low tide

Question 27

Neap Tides

Answer 27

Sun and moon are at right angles. The high tides are lower and the low tides are higher

Question 28

What should you apply to a fathometer reading to determine the depth of water?

Answer 28

Add the draft of the vessel

Question 29

When the sun and moon are in alignment, what type of tides will occur?

Answer 29

Spring

Question 30

The strongest flood and ebb currents generally occur _____.

Answer 30

around half tide

Question 31

Spring tides are tides that _____.

Answer 31

Have lower lows and higher highs than normal

Question 32

Tides can also be affects by

Answer 32

local wind and weather patterns…winds can blow water around. Low pressure fronts can depress sea levels and low pressure fronts can cause tides to be much higher than predicted.

Question 33

On the east coast of North America, charted depths are taken from _____.

Answer 33

mean lower low water

Question 34

Tidal Range

Answer 34

The difference in height between the high tide and the low tide

Question 35

The type of tide that occurs twice daily is called _____.

Answer 35

semi-diurnal

Question 36

The Moon’s declination is

Answer 36

The change in it’s angle in relation to the equator. The two tidal bulges track the changes in lunar delineation, although increasing or decreasing their angles to the equator

Question 37

The major force that causes tides is

Answer 37

gravity

Question 38

The Sun’s declination affects

Answer 38

the seasons and the tides

Question 39

The term tide refers to _____.

Answer 39

Vertical movement of the water

Question 40

When is the sun at its maximum declination

Answer 40

The summer (June 21) and winter (December 22) solstices, which is it at it’s larges angle to the equator.

Question 41

he period at high or low tide during which there is no movement of the water is called _____.

Answer 41

Slack water

Question 42

Due to the relatively close distance, which outweighs the effects of mass, the ______ is the dominant force affecting the Earth’s tides

Answer 42

Moon. Although the sun is 27 million times more massive than the moon, it is 390 times further away. This reduced the sun’s force by 3903 (59 million times) so that is the half of the moon’s.

Question 43

The difference between the heights of low and high tide is the _____.

Answer 43

range

Question 44

Semidiurnal tides

Answer 44

When the two high tides and the two low tides are about the same heights. In the U.S. the is more common on the East Coast

Question 45

Why are there three tidal patters around the world?

Answer 45

Large continents block the westward passed of the tidal bulges as the Earth rotates making complex patterns within each ocean basin. Most areas still have two high and two low tides each day.

Question 46

In Estuaries with strong river flow

Answer 46

the current of the river may

Question 47

When navigating a vessel, you _____.

Answer 47

Should never rely on a floating aid to maintain its exact position

Question 48

Current

Answer 48

The horizontal movement of water which accompanies the rising and falling of the tide.

Question 49

Perigee

Answer 49

The moon is closest to the Earth and as such tidal ranges are above average.

Question 50

The lunar or tidal day is _____.

Answer 50

About 50 minutes longer than the solar day