Properties of WaterChapter 2

Pages 18-47

Marine ScienceMs. Flick

Vocab1. Basins2. Renewable resource3. Nonrenewable

resource4. Overfishing5. Sublimation6. Freezing points7. Melting point8. Boiling point9. Variables10.Independent variable

11.Dependent variable12.Solvent13.Solute14.Solution15.Solubility16.Atom17.Neutrons18.Protons19.Hydrogen bonding20.Cohesion

Vocab Continued.21.Hydrogen bonding22.Cohesion23.Surface tension24.Salinity25.Vaporization26.Freezing27.Condensation28.Brackish29.Estuaries30.Neutral buoyancy

Our Oceans• The ocean covers approximately 71% of Earth’s surface• Our planet’s ocean can be divided into four oceans:– The Pacific– The Atlantic– The Indian– The Arctic

• Basins-large water covered areas between continents; commonly referred to as oceans

• Earth’s ocean contains 97% of the water on Earth• That leaves only 3% of the planet’s water as fresh as

opposed to salt• 2/3 of that freshwater is contained in ice in glaciers and

sea ice caps in Earth’s polar regions

Ocean’s Renewability• The ocean is important for all living things and

influences many of Earth’s processes• The ocean is a resource that replenishes itself naturally

over relatively short periods of time– Renewable resource

• Some resources, such as natural gas and minerals, are exhausted faster than they are naturally replaced– Nonrenewable resources

• Just because the ocean is considered a renewable resource doesn’t mean everything in it is– Overfishing-humans extract fish at rates faster than they

can reproduce making the food source no longer renewable

Activity 1 Procedure1. Prepare two beakers-1 w/ cold water, 1 w/ warm water2. Measure and record the temperature of each3. Place 15 drops of blue food coloring into the cold water

and stir4. What will happen if cold water (blue) from a pipette is

added to the warm water carefully down the side of the beaker? Write down your hypothesis-if/then statement

5. Add droppers full of the cold blue water down the inside wall of the warm water beaker

6. Drop some on one side-then the opposite side7. Note: the dropper tip should be placed immediately

under the surface of the water8. Write down your observations.

Activity 2

1. Prepare 2 beakers-1 w/ warm water and 1 w/ ice cubes

2. Measure the temperature of each beaker’s contents and record

3. Place several ice cubes in the water

Discussion1. How can you explain our observations

of Activity 1?2. What are the ice cubes made of?3. In Activity 1 the cold water stayed on

the bottom. If the ice is colder than the water would you expect it to float on the water?

4. What issues would their be in nature if ice did not float on water?

Investigation 1:Freezing, Melting, and Boiling

Follow the directions in your textbook on pages 23-26 to complete this

investigation.

Write down your findings on your own sheet of paper.

Investigation 2:Surface Tension

Follow the directions in your textbook on pages 26-27 to complete this

investigation.

Write down your findings on your own sheet of paper.

Investigation 3:Floating and Sinking

Follow the directions in your textbook on pages 28-29 to complete this

investigation.

Write down your findings on your own sheet of paper.

Investigation 4:Solutions

Follow the directions in your textbook on pages 30-31 to complete this

investigation.

Write down your findings on your own sheet of paper.

Atoms• Atom-the most basic particle of a unique

element that has the properties of that element• Neutrons-no electrical charge• Protons-a +1 or a positive 1 charge• Around the dense nucleus of each unique atom is

a cloud of tiny, negatively charged electrons• Look at figure 2.16-hydrogen atom• Look at figure 2.17-oxygen atom• Hydrogen and oxygen combine to make a water

molecule

Water Molecules• Look at figure 2.19-water molecules• Hydrogen bonding-the attraction between water

molecules• Cohesion-the property of water making it attracted

to other molecules of water via hydrogen bonding• It is cohesion that allows

water to form drops• Surface tension-the

attraction betweenmolecules at a liquid’ssurface

Salinity

• Salinity-the measure of dissolved salts in water

• Distilled water has no salinity• Water is considered fresh if it contains 1 part

per thousand or less of salts• The average salinity of the ocean is 35 parts

per thousand (35% salt)

Ocean Water• Ocean water carries a lot of minerals• The minerals come from:– Land: freshwater in streams and rivers contains

salts and flows into the ocean– Inside the Earth: volcanoes, vents, and other

processes at the seafloor spew minerals from below Earth’s crust

– Atmosphere: carried by wind and deposited into the ocean

Phase Changes• Vaporization-

liquid to gas• Freezing-

liquid to solid• Condensation-

gas to liquid• Pure water boils at 100 degrees C– 212 degrees F

• Pure water freezes at 0 degrees C– 32 degrees F

• Salt water boils and becomes a gas at a slightly higher temperature than freshwater

• Salt water freezes at a slightly lower temperature

Freshwater and Saltwater Meet• Brackish-water that is somewhere between salt

and fresh– Margrove forests and salt marshes

• Estuaries-where rivers meet the sea– Nurseries of the sea; provide home for many species

of marine life• Plants and animals living here can tolerate wide

ranges in salinity b/c their always changing

Neutral Buoyancy• Some organisms float on top of the ocean• Others live near its bottom• Others make their homes throughout the

water column• Organisms have features that assist them with

floating and sinking or moving up and down-neutral buoyancy