life depends on the unique properities of water. physical properties- can be observed and measured...
TRANSCRIPT
LIFE DEPENDS ON THE UNIQUE PROPERITIES OF WATER
Physical Properties- can be observed and measured Water is a form of
matter Matter- anything that
occupies space and has mass
What happens when you put an ice cube in a glass of water?
Why????
What do you think would happen to a can of coke and diet coke if we placed it into a container of water? Float? Sink? Why?
THE STRUCTURE OF WATER Made up of two
covalently bonded hydrogen atoms to an oxygen atom
Polar Molecule- a molecule that has opposite ends with opposite charges
THE STRUCTURE OF WATER Hydrogen Bond-
weak attraction, bond between a hydrogen atom of a molecule and a slightly negative atom within another molecule.
WATER’S LIFE SUPPORTING PROPERTIES
Cohesion Adhesion Temperature Moderation Low Density of Ice Water’s Ability to Dissolve Other
Substances
COHESION AND ADHESION Cohesion- the
tendency of molecules of the same kind to stick to one another
Adhesion- an attraction between unlike molecules
COHESION AND ADHESION Example: water transport
of trees/plants Evaporation pulls water
which are attached by cohesion up from the roots.
Adhesion of water to the walls of veins resist the downward pull of gravity
Drops On a Penny
How many drops fit on the penny?
Explain the bubble that forms on penny
COHESION AND ADHESION Surface Tension-
cohesion which pulls the molecules at the surface tightly together
When have you experienced surface tension?
http://www.youtube.com/watch?v=6eh93mut9K4&feature=relmfu
Basilisk Lizard http://www.youtube.com/watch?v
=45yabrnryXk&feature=fvw
http://www.teachertube.com/viewVideo.php?video_id=96527
TEMPERATURE MODERATION
Thermal Energy- total amount of energy associated with the random movement of atoms and molecules in a sample of matter.
Temperature- a measure of energy of random motion of particles in a substance
TEMPERATURE MODERATION When two
substances differ in temperature, thermal energy in the form of heat is transferred from the warmer substance to the cooler one
TEMPERATURE MODERATION When you heat
molecules move faster When you cool
molecules move slower Water takes more energy
to heat because of hydrogen bonds
Water retain heat longer because of hydrogen bonds
LOW DENSITY OF ICE Density- amount of
matter in a given volume
In most substances the solid state is more dense than the liquid state
LOW DENSITY OF ICE Water’s solid state is
LESS dense than the liquid state
WHY????? Hydrogen bonds in
ice (solid) keep molecules spaced out
LOW DENSITY OF ICE Since ice is less
dense than water it floats
Ice prevents oceans from freezing over
Ice insulates the liquid water below allowing life to persist
WATER’S ABILITY TO DISSOLVE OTHER SUBSTANCES
Solution- a uniform mixture of two or more substances
Solvent- the substance that dissolves the other substance and is present in greater amounts (water)
Solute- the substance that is dissolved, present in a lesser amount (salt)
WATER’S ABILITY TO DISSOLVE OTHER SUBSTANCES
Aqueous Solution- when water is the solvent
Water molecules surround ions and break them apart
WATER’S ABILITY TO DISSOLVE OTHER SUBSTANCES
Water is the “Universal Solvent”
Water is the main solvent inside all cells, blood, and plant sap
Wrap Up! http://www.youtube.com/watch?v=QH1yphfgfFI
Structure of Water Molecule = Bent. Why? 5 Unique Properties of Water:
1. Cohesion 2. Adhesion 3. Temperature Moderation 4. Low Density of Ice 5. Water’s Ability to Dissolve other Substances
Exit Slip
1. Explain how the structure of water molecules results in attractions among them.
2. Give an example of how cohesion among water molecules is important to living things.
3. Explain one way in which water can moderate temperature.