Schedule
Today: Reading Quiz #3
Salinity
Friday: Lab
Monday: Reading Quiz #4
Learning Objectives
1) Describe the properties of a water molecule
and explain why it is the “universal” solvent.
2) List the four processes that affect salinity and
explain how they affect salinity.
3) Explain the relationship between density,
temperature, and salinity, and how these create
a layered ocean.
LO 2. Describe the properties of a water
molecule and explain why it is the “universal”
solvent.
Water (H2O) is a molecule.
2 hydrogen
atoms are
attached to 1
oxygen atom
with a chemical
bond
H2O is a polar
molecule: one
side is (-) the
other is (+).
Polarity allows for…..
Water
molecules to
attract and
attach to other
water molecules
Polarity allows for….
Salinity
1. We all know the ocean is salty. Come up with
some ways you could determine the amount
of salt that seawater contains
2. Fill in the missing data
Mass of seawater sample = 630 g
Mass of salt in sample = 22g
Mass of water sample = ???
3. Calculate the salinity, or percent of salt, in
this sample.
Salinity answers
• 1. Evaporate saltwater and weigh the salts.
Use conductivity.
• 2. Mass of water = 608 g
• 3. Salinity = mass of salts (solutes)/mass of
seawater (solution)
22 g/630 g = 0.035 or 3.5 percent or 35 per
mil (parts per thousand)
Salinity is the expression for the
amount of dissolved solids (salts)
in seawater.
Each group member will be assigned a task.
Take 5 minutes to research online and then
you will report back to your group.
1) What is the average salinity of the oceans?
What unit is used to express salinity?
2) What are the main solids (salts) dissolved in
seawater. List five.
3) Which two dissolved solids in seawater are
the most abundant? When they are combined
together, what do they form?
4) What are the main sources for salts in the
oceans?
Where do the salts come from?
LO 2. List the four processes that affect salinity
and explain how they affect salinity.
How would the salinity of the oceans vary if the
continents and oceans each covered 50% of Earth's
surface and precipitation and evaporation were similar
to present?
1. salinity would be lower than
today
2. salinity would be higher than
today
3. salinity would be the same as
today
Think. Pair. Share. Write your
answers to the following question
on a piece of paper.
Would evaporation increase or decrease the
salinity of the oceans? Explain your answer.
Would precipitation increase or decrease the
salinity of the oceans? Explain your answer.
Four processes affect salinity
Where is precipitation the highest?
Where is evaporation the highest?
Which location would yield the
highest salinity values?
1.
2.
3.
4.
E
B
H
F
LO 3. Explain the relationship between density,
temperature, and salinity, and how these create
a layered ocean.
1) Predict what will happen when two parcels of
different temperature water are mixed. Share
with your neighbor.
LO 3. Explain the relationship between density,
temperature, and salinity, and how these create
a layered ocean.
1) Predict what will happen when two parcels of
different water with different salinities are
mixed. Share with your neighbor.
Which of the following figures
shows the correct circulation?
The figures show how temperature and density
vary with depth. Explain why they are mirror
images of each other (write--1 minute)
Thermocline
Pycnocline
Both show temperature variation with depth. (A) is
for the equator, (B) is for the Arctic. Why is there a
thermocline at A but not at B? Write--1 minute