Sea Water
Density
“Mass per unit volume”
TEMPERATURE
Water molecules
are at the
maximum
distance from
adjacent
molecules due
to hydrogen
bonding==
Minimum density.
Water makes Hydrogen Bonds
crystalline lattice configuration
Ice (solid phase) is a
crystal with maximal
number of hydrogen
bonds per molecule (4)
Deep circulation in the Atlantic
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.
2: The effects of Temperature on
Density
• Use 35%o water. Warm
•
30 ºC
this water to 30°C. Then
chill it, measuring the
density along the way
with 2 minute intervals.
Remove the hydrometer
between measurements.
5 ºC
3. The Effect of Ice Formation on Density
1. 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
4: Temperature vs Salinity
Although not in the text, we will be setting up the
internal wave tanks again:
1) 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.
2) Predict the outcome and then pull the divider.
3) After the tank settles, reinsert the divider ~1/3
of the tank and stir the layers together.
4) Pull the divider again and answer the
questions.
1500 ml tap water
15 drops of yellow
1500 ml cold water
15 drops of blue