Cambridge International A Level · Marine Science (9693)

Density and pressure: Practice Questions

5 multiple-choice questions marked as you go, and 5 written questions with worked solutions. All on Density and pressure.

10 questions21 marksFree, no account

Question 1

1 mark

In an ocean water column, what is the term used to describe the layer where temperature decreases rapidly with increasing depth?

Question 2

1 mark

A researcher is studying the vertical structure of the water column. They identify a layer where water density increases rapidly with depth. What is the scientific name for this layer?

Question 3

1 mark

A data set shows the following density profile in a coastal region:
\( 0\text{--}50\text{ m}: 1024.1\text{ to } 1024.2\text{ kg m}^{-3} \)
\( 50\text{--}150\text{ m}: 1024.2\text{ to } 1027.5\text{ kg m}^{-3} \)
\( 150\text{--}300\text{ m}: 1027.5\text{ to } 1027.8\text{ kg m}^{-3} \)

In which depth range is the pycnocline located?

Question 4

1 mark

What effect does an increase in salinity have on the density of seawater?

Question 5

1 mark

In a tropical lagoon, intense evaporation occurs during the day followed by a significant drop in temperature at night.

How will these two events specifically affect the density of the surface water?

Question 6

2 marks

State the mechanism by which deep-water mixing occurs when wind blows over the ocean surface.

Write your answer out first, then check it against the worked solution.

Question 7

3 marks

(a) State the formula relating density, mass, and volume.
(b) A sample of dense brine from a salt pan has a volume of \( 0.040\text{ m}^3 \) and a density of \( 1200\text{ kg m}^{-3} \). Calculate the mass of this brine sample in \( \text{kg} \).

Write your answer out first, then check it against the worked solution.

Question 8

2 marks

Define the term halocline and state what causes this layer to form in the water column.

Write your answer out first, then check it against the worked solution.

Question 9

4 marks

(a) A sample of ocean water has a mass of \(51.5\text{ kg}\) and a volume of \(0.050\text{ m}^3\). Calculate the density of the sea water and state the appropriate units.

(b) Explain why the density of sea water increases as the temperature decreases.

(c) State how the density of ice compares to the density of sea water and explain why this property is important for the survival of marine organisms in polar regions.

Write your answer out first, then check it against the worked solution.

Question 10

5 marks

The vertical structure of the open ocean is influenced by physical factors such as temperature, salinity, and pressure.

(a) Describe how an increase in depth affects both pressure and density in the ocean column.

(b) Explain why the formation of a pycnocline/thermocline can act as a physical barrier to the mixing of nutrients between the deep ocean and the surface layer.

(c) Describe two natural mechanisms that cause the physical mixing of surface water and deep water layers.

Write your answer out first, then check it against the worked solution.

* The content provided by thinka is generated by AI and may not always be accurate or up-to-date. Please use it as a supplementary resource and verify with official materials.

You've seen the model answer. Now get yours marked.

This page can show you how a good answer looks. It cannot tell you what your answer was missing. thinka marks your written work against the real mark scheme in about 15 seconds.

Get My Answers Marked Back to the notes

Want more questions like these? Get a fresh set on this topic, graded as you go.