This is an amazing physical property and is why pipes burst and water in cracks shatters rocks in cold temperatures.
The molecular structure of a water molecule is shown in Figure 6. This results in a small net negative charge on the oxygen side of the molecule, and a small net positive charge on the hydrogen side. This is a polar structure in which molecules are weakly attracted to each other and form weak 'hydrogen bonds'. At low temperatures a more ordered packing of water molecules develops and the density is reduced.
Above 3. Seawater is saline and the salt affects the density. The variation in salinity in 7b clearly affects the temperature of maximum density shown in 7c. Much of our knowledge about how the oceans circulate is based on measuring the various parameters such as temperature and salinity from the surface to the sea floor.
The water which makes up this range is called the water column. The most important instrument used by oceanographers is called a CTD Figure 8 , which measures the conductivity and temperature of the seawater and depth pressure. Because pressure in the ocean is proportional to the weight of the water above, it is given by the hydrostatic equation:.
The minus sign indicates that the vertical coordinate z depth is positive in an upwards direction. So by measuring pressure, Equation 2 can be arranged to get depth. Other parameters can also be measured, such as sediment particle density, the amount of chlorophyll present in algae , and so on. If the ocean is m deep, as in Figure 7, a round trip is 10 m and one profile can take almost three hours.
Making the decision to study can be a big step, which is why you'll want a trusted University. Take a look at all Open University courses. If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module , or a module which allows you to count your previous learning towards an Open University qualification.
The components of rocks are eroded and become part of a "salty" solution. Remind students that the word "salt" refers not just to table salt, but to many chemicals that are classified as salts.
Salt water or seawater has characteristics similar to fresh water with some noticeable differences because of the salts that are dissolved in water. The viscosity i. The density of seawater also is higher. Seawater's freezing point is lower than that of pure water and its boiling point is higher. One litre of seawater contains 35 grams of salt - that is approximately 6 teaspoons.
Salt water has more stuff in it than fresh water. That stuff would be the salt, which makes the mass of water greater, without adding much to its volume. Seawater is more dense than fresh water so it sinks beneath freshwater. This means that when rivers flow out into the sea the river freshwater floats on top of the sea water. However when the wind blows and the sea becomes rough, the two waters get all mixed up. The winters in the Arctic and the Antarctic are extremely cold.
The surface waters of the Arctic and Antarctic oceans become very cold and finally freeze. When seawater freezes to form sea ice, salt is squeezed out and moves down into the water. Fresh water floats. Temperature The sea water around the Antarctic continent is always very cold.
The sea water around the equator can be very warm. Cold water is more dense than warm water Cold water is heavier or more dense than warm water. Salinity Salinity is a measure of how much salt there is in water.
What happens when seawater freezes? The cold, salty water sinks to form an ocean current that moves deep underwater toward the equator. The surface water that replaces the sinking water forms an ocean current that moves from the equator toward the Arctic and Antarctic. So, ocean currents are formed because dense water cold and salty sinks. Image source , Antarctic sea ice is made up of mostly fresh water. Connect with us Privacy policy.
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