1 / 27

Videos from sea floor

Videos from sea floor . http://www.youtube.com/watch?v=hmMlspNoZMs http://www.youtube.com/watch?v=rFHtVRKoaUM. Do Now. Use your textbook to look up and write down the definitions to the following terms Heat capacity Latent heat of melting Latent heat of evaporation.

uriel
Télécharger la présentation

Videos from sea floor

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Videos from sea floor • http://www.youtube.com/watch?v=hmMlspNoZMs • http://www.youtube.com/watch?v=rFHtVRKoaUM

  2. Do Now • Use your textbook to look up and write down the definitions to the following terms • Heat capacity • Latent heat of melting • Latent heat of evaporation

  3. Chemical and Physical Features of Seawater and the World Ocean Chapter 3

  4. Surface Tension • http://www.youtube.com/watch?v=2suY9h7xnKg

  5. Hydrogen Bonds • Attractions between water molecules • Weak • Temperature reflects average speed of the molecules • D=m/v • As sea water gets colder, it gets more dense.

  6. Less Dense Frozen

  7. Melting Ice • Takes a lot of heat. • Hydrogen bonds have to be broken. • The amount of heat required to melt a substance is called the latent heat of melting • http://www.youtube.com/watch?v=MpDJmRydR04

  8. Heat capacity • The amount of heat it takes to raise a substances temperature by a given amount. • Water has a high heat capacity

  9. Latent heat of evaporation • Water absorbs a great deal of heat when it evaporates.

  10. Universal Solvent • Water is very good at dissolving salts • Charged atoms or groups of atoms are known as ions • Salts have much stronger electric charges than the opposite end of the water molecule. • Bonds between ions are stronger than hydrogen bonds

  11. Water dissolves salt

  12. Seawater • Characteristics of seawater are due to the nature of pure water and solutes • Weathering • Volcanoes • Hydrothermal vents.

  13. Salt composition • Seawater contains a little of almost everything, most of the solutes are made up of a small group of ions • 6 ions compose over 99% of the solids dissolved in seawater • Sodium chloride accounts for 85%

  14. Salinity • The total amount of salt dissolved in seawater • How is it expressed? • Parts per thousand • Because of the electrical charges ions are good conductors of electricity • Electric conductivity of seawater therefore reflects salt concentration • Practical salinity units (psu)

  15. Salinity on organisms • Organisms are affected by total amount of salt and the type of salt • Examine salts left after evaporation

  16. Table 3.1

  17. Rule of constant proportions • William Dittmar – chemist analyzed samples from the Challenger expedition. • Found that percentage of the various ions in seawater remained constant even though the total amount of salt varied from place to place • Oceans are chemically well mixed • Varies by addition or subtraction of pure water

  18. Average Salinity • 35 0/00 • Open ocean varies little between 33 0/00 and 37 0/00 • The variation mostly depends on evaporation and precipitation

  19. Red Sea • The Red Sea is very salty • About 40 0/00 • Salinity affects the density of water like temperature • Salty water is more dense than freshwater • Discovery Ed Red Sea clip

  20. Salt water • Freezes at a lower temperature that freshwater • Oceans are less prone to freezing than lakes and rivers are • Temperature varies more in the ocean than salinity • Open ocean range is about -2 degrees C and 30 degrees C

  21. Do Now

  22. Measuring temp. and salinity • Specially designed bottles and thermometers on a wire to the desired depth • A weight known as a messenger is released to slide down the wire. • Temperature profile

  23. Temperature profile

  24. CTDs • Conductivity, temperature and depth in the water column • Used along with other instruments. • Bathythermographs – measure temp but not salinity

  25. Complications w/ samples • What are some complications that scientists may face when collecting samples? • Hmm.. • Trying to get samples from multiple sites • Weather and climate variability

  26. Solutions • What are some solutions to these problems? • Hmm… • Instruments could drift with the currents

More Related