here are the answers did you get any right


Quiz answers
1.Alexander the Great.

2.In the first US Divers mail order catalogue, each product was given a letter code. The valves were codes J and K.

3.Swiss mathematician and computer guru Hannes Keller
holds the all-time deepest open water dive record.
He dived to 1000 feet of sea water off California in 1962,
breathing a mixed gas.
The cave diving depth record was held several times by
diving hero and high school mathematics teacher Sheck Exley.


4.No. Biological material is completely incinerated because of the enormous partial pressure of oxygen.

5.In air, there is a slight delay between arrival of a sound at one ear and at the other. In water, sound travels 8 times faster, and the delay is so short as to be imperceptible.

6.m'aider is French for (to) help me.

7.Pan-pan. (Mayday is "we are in grave and imminent danger to life"; pan-pan is "we are in danger"; securite is "there is danger/risk to vessels".)

8.The same as it is at the surface: about 1 kilogram per litre (62 lb/cu ft). Water is practically incompressible at these pressures.

9.The Australian box jellyfish Chironex fleckeri (a.k.a. Sea Wasp, Indringa, Fire Medusa).

10.The Belize Barrier Reef.

11.hyperbaric (Hyperbaric Medicine) means pressures greater than normal; hypobaric means pressures less than normal; alternobaric (Alternobaric Vertigo) refers to alternating or changing pressures; and dysbaric (Dysbaric Osteonecrosis) refers to unwanted or damaging effects of pressure.

12.He is credited with inventing (on paper) the first scuba apparatus.

13.The egg case of some sharks.

14.5500 metres (18,000 feet).

15.Cold-blooded (they do not produce their own body heat).

16.Yes. Fish drown if the oxygen content of the water falls too far. Also, some sharks have to keep swimming in order to circulate water over their gills; if they become entangled they can drown.

17.Yes. Many bony fish have swim bladders which are filled with air and control their buoyancy. If they are dragged up in a net, they can suffer decompression barotrauma.

18.He tasted a pufferfish (the liver and roe), almost succumbing to tetrodotoxin poisoning.

19.Three.

20.Water filters out the longer wavelengths of light (red - yellow) more readily than the shorter wavelengths (blue - violet) so that everything appears more blueish at depth.

21.They provided suicide pills.
In 1962, a U2 spy plane piloted by USAF Major Gary Powers was shot down over the Soviet Union. Powers disobeyed his orders to commit suicide if captured. His suicide pill contained saxitoxin, a lethal neurotoxin found in shellfish.

22.It is arbitrary - there is no physiological reason for choosing 40 metres in particular.

23.There are fish at all depths. In 1960 the crew of the bathyscaphe Trieste saw a sole on the bottom of the Mariana Trench, at a depth of 10933 metres.

24.Halley patented the first practicable diving bell (with a replenishable air supply) in 1690.

25.Expelling its zooxanthellae.
The animals which make up the coral colony normally live in symbiosis with algae called zooxanthellae, which provide most of the animal's energy by photosynthesis. Pigment in the zooxanthellae gives coral its blue or brown colour. Under stress the coral zooids expel their zooxanthellae (or most of them) and consequently lose colour.

26.Mostly argon. Unpolluted dry air at sea level is 78.08% Nitrogen, 20.95% Oxygen, 0.93% Argon, 0.03% Carbon Dioxide, and traces of Ozone and inert gases. Moist air contains 0-4% water vapour, and polluted air contains fractions of a percent of sulphur gases.

27.The American War of Independence. The American submarine Turtle attacked HMS Eagle in New York harbour in 1776. (This is the first authenticated attack by a submarine.)

28The mouth of a sea urchin.

29.Only the dugong and manatee.

30.French physiologist Paul Bert, in 1878.

31.Ten (8 short arms, two long tentacles).

32.Operculum: 1. the hard bony flap covering the gill slits in fish; 2. A plate-like structure on the foot of a gastropod that seals its shell; 3. any lid-like covering.

33.A fathom is 6 feet. A cable's length is 100 fathoms. Ten cables' lengths is one nautical mile. A nautical mile is the length of one minute of longitude at the equator.

34.Nekton and benthos. (Plankton are organisms which drift; nekton are organisms which can swim; benthos live on the bottom).

35.Haldane's pioneering experiments on decompression were performed on goats. Goats are extremely fond of corn, so it was a sign of illness when they could not even be tempted with corn.

36.This is not a particular property of diver's knives. The stainless steel used for making knives is less corrosion-resistant than the stainless steel used for making dishes, plates etc. The composition of stainless steel involves a tradeoff between its resistance to corrosion and its ability to hold a sharp edge.

37.The blue whale, Balaeoptera musculus.

38.Yes for helium, No for oxygen. The oxygen content of body tissues is regulated by the haemoglobin buffer and does not conform to Henry's Law. [Oxygen toxicity occurs when this system is overwhelmed.]

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Question 5 should read sound travels 4 times faster underwater than in air if you got on with your divemaster course bob you would of known this!

that would have been good if i read any of the questions i just copied from somewhere else.

but to be technical

Science of Sound in the Sea

Sound Movement
How fast does sound travel?
We know that sound moves. How fast does it move? Sound moves about 1500 meters per second in seawater. That's approximately 15 football fields end-to-end in one second!! Pretty impressive! (Sound moves much more slowly in air, at about 340 meters per second, only 3 football fields a second).
Unfortunately, the answer is really not quite that simple. The speed of sound in seawater is not a constant value. It varies by a small amount (a few percent) from place to place, season to season, morning to evening, and with water depth. Although the variations in the speed of sound are not large, they have important effects on how sound travels in the ocean.
What makes the sound speed change? It is affected by the oceanographic variables of temperature, salinity, and pressure. We can look at the effect of each of these variables on the sound speed by focusing on one spot in the ocean. When oceanographers look at the change of an oceanographic variable with water depth, they call it a profile. Here we will examine the temperature profile, the salinity profile, and the pressure profile. Similar to the profile of your face that gives a side view of your face, an oceanographic profile gives you a side view of the ocean at that location from top to bottom. It looks at how that characteristic of the ocean changes as you go from the sea surface straight down to the seafloor. The spot we are going to explore is in the middle of the deep ocean.
Here are basic profiles for a site in the deep, open ocean roughly half-way between the equator and the North or South pole. In these profiles, temperature decreases as the water gets deeper while salinity and pressure increase with water depth. Here we are referring to the ocean pressure due to the weight of the overlying water (equilibrium pressure), not to the pressure associated with a sound wave, which is much, much smaller. In general, temperature usually decreases with depth, salinity can either increase or decrease with depth, and pressure always increases with depth.
From these profiles, you can see that temperature changes a large amount, decreasing from 20 degrees Celsius (°C) near the surface in mid-latitudes to 2 degrees Celsius (°C) near the bottom of the ocean. On the other hand, salinity changes by only a small amount, from 34 to 35 Practical Salinity Units (PSU), approximately 34 to 35 parts per thousand (ppt). Finally, pressure increases by a large amount, from 0 at the surface to 500 atmospheres (atm) at the bottom.

The speed of sound in water increases with increasing water temperature, increasing salinity and increasing pressure (depth). The approximate change in the speed of sound with a change in each property is:

Temperature 1°C = 4.0 m/s
Salinity 1PSU = 1.4 m/s
Depth (pressure) 1km = 17 m/s

Knowing that the speed of sound increases with increasing temperature, salinity, and pressure, what would you guess the typical sound speed profile looks like?
Here is a typical sound speed profile for the deep, open ocean in mid-latitudes. Did you guess correctly?
The decrease in sound speed near the surface is due to decreasing temperature. The sound speed at the surface is fast because the temperature is high from the sun warming the upper layers of the ocean. As the depth increases, the temperature gets colder and colder until it reaches a nearly constant value. Since the temperature is now constant, the pressure of the water has the largest effect on sound speed. Because pressure increases with depth, sound speed increases with depth. Salinity has a much smaller effect on sound speed than temperature or pressure at most locations in the ocean. This is because the effect of salinity on sound speed is small and salinity changes in the open ocean are small. Near shore and in estuaries, where the salinity varies greatly, salinity can have a more important effect on the speed of sound in water.
It is important to understand that the way sound moves is very much dependent on the conditions of the ocean. The sound speed minimum at roughly 1000 meter depth in mid-latitudes creates a sound channel that lets sound travel long distances in the ocean. The refraction section provides more information on how the sound speed minimum focuses sound waves into the channel.
The speed of sound in seawater is calculated using very sophisticated mathematical equations. Check out the resources listed below to learn more about sound speed and how it is calculated.

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