Earth’s Hydrosphere

aka – The water Planet!

Key Terms: •Polar Molecule•Capillary action•Surface tension•Solution•Solvent•Specific heat•Evaporation•Condensation•Adhesion•Cohesion

Hydrosphere: the water (as vapors,

lakes, oceans etc.) of the earth.

THE STRUCTURE OF WATER

•Water is made up of atoms – just like all matter.

•Atoms attach (bond) together to form molecules.

•Two hydrogen atoms bonded to an oxygen atom form a water molecule

Chemical Formula H₂O

+ +

__

Hydrogen Atom: each hydrogen atom has a slight positive charge

Hydrogen Atom

Oxygen Atom: The oxygen atom has a slight negative charge

•A molecule that has electrically charged areas is a polar molecule.

• Because water is a polar molecule it is called a polar substance.

Key Properties of Water

The properties of water include:-Capillary action-Surface Tension-Universal Solvent-High specific heat

Capillary Action: is the combined force of attraction among water molecules and with the molecules of surrounding materials.

• Capillary Action allows water to move through materials with pores inside.

• This action also causes water molecules to cling to the fibers of materials like paper and cloth.

Question:

What is the advantage of the interaction of water and fibers in clothing?

Surface Tension:is the tightness across the

surface of water that is caused by the polar molecules pulling on one another.

Universal Solvent:

Solution: is a mixture that forms when one substance dissolves another.

Solvent: is the substance doing the dissolving.

•Water can dissolve solids, liquids, and many gases: oxygen and carbon dioxide.

• Nonpolar substances do not dissolve well in water. A nonpolar substance has no charged region on the molecule.

Specific Heat: is the amount of heat needed

to increase the temperature of a certain mass of a substance by 1°C.

Water requires a lot of heat to increase its temperature due to the strong attraction among its molecules.

Question:

What effect does water’s high specific heat index have on land areas? How does it affect where you live?

The three states of water

1. Solid2. Liquid3. Gas (vapor)

•Solid state means that the molecules are close together and form a rigid structure.

•Liquid state means that the molecules move more freely.

•Gas state means the molecules move VERY freely and spread out to fill up space.•The boiling point of water is 100°C which then turns it into a gas.

•Evaporation: is the process by which molecules at the surface of a liquid absorb enough energy to change to the gaseous state.

What are some examples of Evaporation?

Condensation:is the process by which a gas

changes to a liquid.

•This process begins when the gas (water vapors) cools down and the molecules slow down.•When the gas reaches 100°C and cooler it begins to change to the liquid state before boiling occurred.

•Water begins to freeze at 0°C and turn into its solid form.

•Water begins melting at 0°C and turn into its liquid form.

Changing states of water recap:

•Water moves between the liquid and gaseous states by evaporation and condensation.

•Water moves between the liquid and solid states by freezing and melting.

Adhesion and CohesionAdhesion: the ability of water to stick firmly to something not similar to it. (i.e. water to another substance)

Cohesion: the force of attraction by which the molecules of water, solid or liquid, tend to remain together. ( i.e. water to water)

Activity:

Frayer models: