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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????
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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.