Sea Water Density

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Sea Water Density

• Mass per unit volume

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TEMPERATURE

• Water molecules are at the maximum distance from
  adjacent molecules due to hydrogen bonding
• Minimum density.

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Water makes Hydrogen Bonds
Ice (solid phase) is a crystal with maximal
number of hydrogen bonds per molecule (4)
crystalline lattice configuration
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Deep circulation in the Atlantic
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1. The effect of salinity on density
Use hydrometer and thermometer to measure the
density and temperature for three solution of
different salinities 10, 20, 35 Hydrometer
must be floating Determine what the theoretical
density should be at a given temperature and
salinity.
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2 The effects of Temperature on Density

• Use 35o water. Warm this water to 30C. Then
  chill it, measuring the density along the way
  with 2 minute intervals.
• Remove the hydrometer between measurements.

30 ºC
5 ºC
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3. The Effect of Ice Formation on Density

• Let 1/3 of your sample to turn into ice.
• 2. Transfer the remaining liquid that does not
  freeze brine into graduate. (you need 85 mL to
  float the hydrometer)
• 3. Measure the temperature with the thermometer
  and measure the density with a hydrometer at 5oC.
• DO NOT STIR WITH THE THERMOMETER
• DO NOT LEAVE THE THERMOMETER IN THE FLASK WHILE
  FREEZING

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4 Temperature vs Salinity

• Although not in the text, we will be setting up
  the internal wave tanks again
• Place the divider in the center and put 2.5
  liters of cold (blue) fresh water in one half and
  2.5 liters room temperature (red) fresh water in
  the other half.
• Predict the outcome and then pull the divider.
• After the tank settles, reinsert the divider 1/3
  of the tank and stir the layers together.
• Pull the divider again and answer the questions.

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1500 ml tap water 15 drops of yellow
1500 ml cold water 15 drops of blue