Effect of salinity and temperature on wave propagation.

1. Chemistry Effect of salinity and temperature on wave propagation.

2. Salinity Salt concentration in water influences density and; therefore wave propagation in salt water in majorly impacted by salinity. Density increases as salinity increases, simply because Na+ and Cl- ions have more mass than the oxygen and hydrogen atoms in fresh water. This increased density means that the water will freeze at a lower temperature. When ice forms on top of water in colder environments, the salt cannot form part of the ice, and, as a result, is rejected and adds to the salinity and density of the water below the ice. This process is called brine rejection. This process explains why ocean water is denser and saltier in colder environments, such as the arctic.

3. Temperature Fresh, pure water has its maximum density at 4 degrees Celsius. Other factors influence this maximum; one of those being salinity. However, we know from brine rejection that colder environmental temperatures can result in an increase in salinity. Therefore, we can draw the conclusion that temperature has an indirect on density, and that as temperature decreases, density increases ( in the case of salt water).

4. Biology Whales; why echolocation? The ins and outs of whale communication.

5. Echolocation Odontocetes (toothed whales) communicate, navigate and hunt via echolocation. Echolocation involves the production of sound waves that originate in the whales head, and pass through the melon (Figure 1). Waves propagate until reaching an object, at which point the waves are bounced off said object and propagate back to the whale. The whale attains a great deal information from the return wave; the distance the object is from the whale, the size, the speed at which the object is moving, the shape, and many other key details. Figure 1 The echolocation sounds produced by whales consist of a series of low frequency clicks. These clicks follow a path through the whale’s skull, tweaking and refining the sound until it is appropriate for emission.

6. Related Neurology Although there is little information available in regards to echolocation neuroscience amongst toothed whales, there has been research done regarding an organism included in the same order; the dolphin. The advanced requirements that coincide with echolocation that are fulfilled by dolphins can be linked to the ration of brain size to body size; when measured in relation, only human brains are larger. Sophistically developed parts of their brains include the cerebellum ( movement and cognitive function) and the auditory nuclei. There is also evidence that echolocation information is paired with other types of sensory information, such as vision.

7. Bibliography • http://www.afsc.noaa.gov/nmml/education/cetaceans/cetaceaechol.php • https://www.google.ca/search?q=Odontocete+whale+echolocation&espv=210&es_sm=93&tbm=isch&imgil=BLyacDiwWnT9CM%253A%253Bhttps%253A%252F%252Fencrypted-tbn2.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcQZp0B9t4vcPnDVbR9bdA17oBZJcoiPH8SdgjKgr-8E6SnzXwDRFQ%253B651%253B304%253BDIlObRbfUsgH8M%253Bhttp%25253A%25252F%25252Fpalaeo.gly.bris.ac.uk%25252Fpalaeofiles%25252Fwhales%25252Fodontoceti.htm&source=iu&usg=__GBeI9m7WN61b0t5opXs72-GnUQI%3D&sa=X&ei=dlE7U8GpDqm52AW7woD4Dw&ved=0CHgQ9QEwCA#facrc=_&imgdii=_&imgrc=BLyacDiwWnT9CM%253A%3BDIlObRbfUsgH8M%3Bhttp%253A%252F%252Fpalaeo.gly.bris.ac.uk%252Fpalaeofiles%252Fwhales%252Fpictures%252Fecholocation.gif%3Bhttp%253A%252F%252Fpalaeo.gly.bris.ac.uk%252Fpalaeofiles%252Fwhales%252Fodontoceti.htm%3B651%3B304 • http://www.enchantedlearning.com/subjects/whales/glossary/Echolocation.shtml • http://www.mapoflife.org/topics/topic_369_Echolocation-in-toothed-whales-and-ground-dwelling-mammals/ • http://en.wikipedia.org/wiki/Whale_vocalization • http://en.wikipedia.org/wiki/Properties_of_water#Density_of_saltwater_and_ice • http://hypertextbook.com/facts/2007/AllenMa.shtml