The motion of the ocean

Question 1

what determines the size of a wave

Answer 1

wind speed, duration and fetch

Question 2

how does the energy of a wave dissipate

Answer 2

friction

Question 3

what is stokes drift

Answer 3

the small net flow of water causes by a wave

Question 4

does energy increase or decrease with depth

Answer 4

decrease

Question 5

when will you stop feeling a wave

Answer 5

at half the wave length deep

Question 6

what is the wave base

Answer 6

half the wave length deep, the effective lower limit of wave motion

Question 7

what is a fully developed sea?

Answer 7

wave energy in = wave energy out

Question 8

what is surf

Answer 8

the wave activity between the line of breaking waves and the shore

Question 9

at what depth do waves usually break

Answer 9

wave height depth or 1.5 x wave height depth

Question 10

what is wave refraction

Answer 10

change in direction of a series of waves moving in shallow water at an angle to the shoreline. Due to trend of breaking wave becoming realigned to parallel bottom contours of the bed

Question 11

how is a longshore current created

Answer 11

incoming wave resolved in two directions due to refraction: perpendicular and parallel to the shore

Question 12

what is the dissipated energy from waves used for

Answer 12

erosion and transport

Question 13

what factor impacts the energy dissipation and therefore amount of erosion?

Answer 13

nature of the seafloor gradient

Question 14

what is the time interval between wave peaks called

Answer 14

period

Question 15

what is the number of peaks per second called

Answer 15

frequency

Question 16

what are capillary waves

Answer 16

short wavelengths with rapid periods

Question 17

which two forces are balanced in tides

Answer 17

inertial and gravitational

Question 18

explain how the tides are formed

Answer 18

water on side of earth nearest the moon is pulled by gravity, this creates a bulge of water. Inertia keeps objects moving straight ahead away from the centre of the earth-moon system (works against gravity). Inertia equal at all points. On the moon side, gravity exceeds inertia, causing the tide. Water from poles drawn to the equator

Question 19

explain the spring and neap tides

Answer 19

sun has smaller gravitational pull. when it lines up with the tidal bulge of the moon we get spring tide. When the bulges are at opposite sides (sun and moon at right angles) we get neap tide.

Question 20

what is submergence

Answer 20

rise of water in relation to the land

Question 21

what is emergence

Answer 21

lowering of water in relation to the land

Question 22

what is the main cause of emergence or submergence

Answer 22

glaciers melting or building up

Question 23

what is the main cause of local emergence and submergence

Answer 23

tectonic activity

Question 24

how much higher would sea levels be if all ice on land melted entirely

Answer 24

65-80m

Question 25

what impacts would melting sea ice have

Answer 25

not a dramatic impact on sea levels as its already in the sea, but would decrease salinity and impact thermohaline circulation

Question 26

name 6 ways that the ocean is important to humans

Answer 26

energy (oil from rocks and renewable hydro energy), food, employment, undersea mining, transport for goods and people, climate moderation