January 30th lecture

Question 1

What is heat capacity?

Answer 1

The amount of heat needed to heat 1g o fa substance by 1C

Question 2

What is Sensible heat?

Answer 2

Heat that raises or lowers the temperature of an object but does not change its phase

Question 3

What is latent heat?

Answer 3

Heat added or removed that does not change the temperature of a substance but leads to a change in phase.

Question 4

What is ocean waters light absorbing properties?

Answer 4

Water absorbed Electromagnetic radiation, with the depth of penetration depending on the wavelength.

Question 5

How deep can most EM radation penetrate in the ocean?

Answer 5

only a few cm’s or m’s at most.

Question 6

How far can light penetrate the ocean’s water?

Answer 6

Light can go farther than most Electromagnetic radiation, although the distance is still dependent on wavelength.

on average light goes down 100m, where about 1% if its energy remains

Question 7

What is the Photic Zone?

Answer 7

The area of the ocean where photosynthesis occurs, within the top 100m of the ocean.

Question 8

Why is light penetrance reduced near the coast and in estuarine waters?

Answer 8

Due to the large amounts of suspended sediments in the water

Question 9

What wavelength of light goes deepest in ocean water?

Answer 9

blue light range goes the deepest in the ocean water

Question 10

How does the low penetration of light influence how we study the ocean?

Answer 10

The low penetration of light into the ocean is why we radar and lasers cannot be used to study the oceans interior. as they get absorbed quickly

Question 11

How does light scatter or reflect?

Answer 11

Light is scattered when photons bounce off water molecules and/or suspended sediments

Question 12

In general what direction does scattering happen in the ocean?

Answer 12

all directions

Question 13

What wavelength of light has the greatest chance of being scattered?

Answer 13

Blue light as it penetrates the deepest (smallest wavelength)

Question 14

Why is running water seen as green or brown?

Answer 14

it is due to the mixing of scatterd light within the water.

Question 15

How can we determine ocean color?

Answer 15

It is determined by the location of phytoplankton, sediments, etc.

as particles reflect light, and we see the color that they reflect.

Question 16

How is sound transmitted in the ocean?

Answer 16

Sound is transmitted by the vibration of adjacent molecules ( and thus can’t travel in a vacuum )

Question 17

How are sound waves produced?

Answer 17

Sound waves are produced through pressure changes between molecules

Question 18

Is sound also affect as much as light is by the ocean?

Answer 18

No, that is why we can use Sonar to study the ocean. and why whales communicate using sound waves.

Question 19

How fast is the speed of sound in water compaired to air?

Answer 19

Sound waves travel 4x faster underwater than in air

Question 20

What increases the speed of sound underwater?

Answer 20

The speed of sound increases as salinity, temperature, and pressure increase.

Question 21

Are sound waves that travel vertically affected by changes in density among ocean layers?

Answer 21

No very much no

Question 22

Are sound waves that travel at different angels other than vertically affected by density differences in water?

Answer 22

Yes , greatly effected. They are deflected as they hit sloping density layers

Question 23

What is a shadow zone?

Answer 23

A region where sound pulses can’t reach

Question 24

What is a sound channel?

Answer 24

A region associated with the sound speed minimum where sound waves that enter are trapped. This allows them to travel great distances with little loss of energy.

Question 25

What is acoustic thermography?

Answer 25

This is a technique to accurately determine travel times in water over large distances by noting how the speed of sound changes with temperature

Question 26

How is thermography being used today?

Answer 26

It is used to help detect the effects of climate change

Question 27

How does Thermography work?

Answer 27

You send a low frequency sound in a sound channel around the world, and measure the time taken to get to certin points at different locations around the globe.

because heat causes sound to travel faster, if the ocean is warming then the sound waves will complete the trip faster than before when it was at a lower temperature.