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### Re: Dynamic Planet (Oceanography)

Posted: September 12th, 2019, 6:04 pm
Good Questions @JoeyC

NGL, I can't believe I didn't think about Q2 right

I'll try basic maths...

1. A basketball in water. Mass of 1 kg, Radius is 1 meter. let's say gravity is 10. What is the bouyant force, volume of water displaced by ball, Avg density of ball?

2. The salinity of 50 grams of water is 40 parts per thousand, how many ounces of pure water would need to evaporate to raise the salinity to 45 parts per thousand?

3. The magnetosphere is created by what layer of Earth? What feauture of the magnetosphere do we use to date oceanic crust?

4. What is an instrument that measures the direction and speed of ocean currents? How does it work(two words will suffice)?
1. buoyant force = 0.04 N displacement = 4 m^3 density = 0.2 kg/m^3 maybe try to have more than 1 sig fig next time?
2. 5.6 g or 0.20 oz of water.
3. ionosphere, periodic magnetic reversals (by measuring the orientation of magnetic minerals in the crust).
4. current meter, water movement orients the rotor in the direction of flow and the rotor spins in proportion to current speed.

### Re: Dynamic Planet (Oceanography)

Posted: September 13th, 2019, 6:46 am
Good Questions @JoeyC

NGL, I can't believe I didn't think about Q2 right

I'll try basic maths...

1. A basketball in water. Mass of 1 kg, Radius is 1 meter. let's say gravity is 10. What is the bouyant force, volume of water displaced by ball, Avg density of ball?

2. The salinity of 50 grams of water is 40 parts per thousand, how many ounces of pure water would need to evaporate to raise the salinity to 45 parts per thousand?

3. The magnetosphere is created by what layer of Earth? What feauture of the magnetosphere do we use to date oceanic crust?

4. What is an instrument that measures the direction and speed of ocean currents? How does it work(two words will suffice)?
1. buoyant force = 0.04 N displacement = 4 m^3 density = 0.2 kg/m^3 maybe try to have more than 1 sig fig next time?
2. 5.6 g or 0.20 oz of water.
3. ionosphere, periodic magnetic reversals (by measuring the orientation of magnetic minerals in the crust).
4. current meter, water movement orients the rotor in the direction of flow and the rotor spins in proportion to current speed.
Cool, lol wasn't thinking about sigfigs at all. 1) bouyant Force is equal to the force of gravity which is 1kg * gravity = 10Newtons. Forrmula for volume bouyant Force = Volume*Gravity*density which gives 1/1000 m^3 or . Density is correct.
2) Correct, I believe
3) Outer Core has electric currents which generate the Magnetosphere. Other part is correct
4) I was thinking ADCP, Doppler Shift, but yeah ig that works

### Re: Dynamic Planet (Oceanography)

Posted: September 13th, 2019, 9:08 am
1. What is a guyot? How does one form?

2. Describe the three stages of atoll formation. Who first proposed this theory?

3. If a deep-water wave with a wavelength of 12 m is moving at a speed of 50 m/s in 2500 m deep water, what is its period?

4. For the wave in question 3, what is the maximum amplitude it can have before it breaks, assuming it remains in deep water?

### Re: Dynamic Planet (Oceanography)

Posted: September 13th, 2019, 11:46 am
1. What is a guyot? How does one form?

2. Describe the three stages of atoll formation. Who first proposed this theory?

3. If a deep-water wave with a wavelength of 12 m is moving at a speed of 50 m/s in 2500 m deep water, what is its period?

4. For the wave in question 3, what is the maximum amplitude it can have before it breaks, assuming it remains in deep water?
1. It’s like a flattopped seamount, which formed by erosion of a seamount (formed by volcanism) to have a flat top
2. Atolls are formed by
A. Volcanism forming an island
B. Erosion of the island and formation of a fringing reef, and it lowers in elevation
C. Complete submersion and the island is now a lagoon, oh and also formation of a barrier reef
I feel like I had on my old notes that Darwin came up with it lol
3. 2.77 s, I used the formula wavelength = (g*T^2)/2pi, so if I messed up somewhere lmk lol
4. I’m not so sure abt this one, wouldn’t it just break when it touched the bottom, so like, 2500 m?
Worth a shot lol

### Re: Dynamic Planet (Oceanography)

Posted: September 21st, 2019, 5:34 pm
Generally, people ask one question or questions that relate to each other

Although I'm not hating this format either.

### Re: Dynamic Planet (Oceanography)

Posted: October 14th, 2019, 9:08 am
1. What is a guyot? How does one form?

2. Describe the three stages of atoll formation. Who first proposed this theory?

3. If a deep-water wave with a wavelength of 12 m is moving at a speed of 50 m/s in 2500 m deep water, what is its period?

4. For the wave in question 3, what is the maximum amplitude it can have before it breaks, assuming it remains in deep water?
1. It’s like a flattopped seamount, which formed by erosion of a seamount (formed by volcanism) to have a flat top
2. Atolls are formed by
A. Volcanism forming an island
B. Erosion of the island and formation of a fringing reef, and it lowers in elevation
C. Complete submersion and the island is now a lagoon, oh and also formation of a barrier reef
I feel like I had on my old notes that Darwin came up with it lol
3. 2.77 s, I used the formula wavelength = (g*T^2)/2pi, so if I messed up somewhere lmk lol
4. I’m not so sure abt this one, wouldn’t it just break when it touched the bottom, so like, 2500 m?
Worth a shot lol
Since nobody has confirmed these, I guess I will.

All look correct except #4. The answer for that one is 0.857 m, or 6/7 meters. The ratio of wave height to wavelength cannot exceed 1:7 without breaking, so max wave height is 12/7 m, and amplitude is half of wave height, so it would be 6/7 m. I'll ask some now:
1. What kind of data is a Nansen bottle used to collect?
2. What new tool has replaced the Nansen bottle for collection purposes?

### Re: Dynamic Planet (Oceanography)

Posted: October 14th, 2019, 9:56 am
I think that this is what you're looking for....
Answer: Temperature at specific depths. The Nansen bottle was replaced by the Niskin bottle. Question: Who were the scientists credited with creating the theory of Magnetic Reversals? When was the last magnetic reversal?

***EDIT**** Someone should make a notesheet of all the common equations used for this event and hit everyone on the forums up. It'd be soooooo nice.