warm up how many paper clips will fit in the glass of water before the water spills over?
TRANSCRIPT
Warm upWarm up
How many paper clips will fit in the glass of How many paper clips will fit in the glass of water before the water spills over?water before the water spills over?
Hydrogen Bonds:•Weak, polar bonds.•Form rapidly and break rapidly
Example:Between water molecules
Hydrogen Bonding explains the Hydrogen Bonding explains the following properties of water:following properties of water:
1. Cohesion 2. Adhesion 3. High heat capacity 4. Evaporative cooling 5. Low density of ice 6. The ability of water to dissolve many
substances.
Water & SolutionsWater & Solutions
Water = major part of Water = major part of cellscells 70% of your body – 2/3 of molecules70% of your body – 2/3 of molecules
Water Water stores heat stores heat efficiently = heats efficiently = heats slowly and retains heat longer! Release slowly and retains heat longer! Release heat through evaporation. heat through evaporation.
MAINTAINS MAINTAINS HOMEOSTASISHOMEOSTASIS
Water & SolutionsWater & Solutions
Water bonds to itself & other substancesWater bonds to itself & other substances
COHESIONCOHESION = attraction between substances = attraction between substances of the of the SAMESAME kind. kind. Hydrogen bonds link molecules togetherHydrogen bonds link molecules together Like holding handsLike holding hands Surface Surface tensiontension – prevents surface of water from – prevents surface of water from
breaking / stretchingbreaking / stretching
The water’s surface tension allows this insect to remain supported.
http://www.realeyz.com/photo/macro/photos/leaf_drops.jpg
CohesionMolecules of the same substance are attracted to each other
•Leads to surface tension and water droplets
Water & SolutionsWater & Solutions
ADHESIONADHESION = attraction between = attraction between substances that are substances that are DIFFERENTDIFFERENT
CapillaryCapillary action = process where water action = process where water molecules move upward through narrow tube molecules move upward through narrow tube (ex: plant stem)(ex: plant stem)
• Stronger than downward gravity force.Stronger than downward gravity force.
AdhesionAttraction between molecules of different substances
Ex: glass and water
http://staff.um.edu.mt/rlib1/sm/wpe32.jpg
CapillarityAttraction that causes the surface of the liquid to rise when in contact with a solid.
Cohesion-Adhesion Theory
-As water evaporates from leaves, it tugs on the water molecules below-Cohesion and adhesion pull water up and replace missing water molecules-Water enters the roots by osmosis
www.emc.maricopa.edu/.../BioBookPLANTHORM.html
Did you ever wonder: How does water move from roots to leaves when a tree doesn’t have a heart to pump the water?
Water Dissolves Many SubstancesWater Dissolves Many Substances
SOLUTION SOLUTION = A mixture in which one or more = A mixture in which one or more substances are evenly distributed in another. substances are evenly distributed in another. (Salt Water)(Salt Water)
EX: Osmosis = movement of material/nutrients EX: Osmosis = movement of material/nutrients between cells.between cells.
Like dissolves likeLike dissolves like
Polar molecules Polar molecules dissolve easilydissolve easily Example: alcohol and Example: alcohol and
water water
LIKE DISSOLVES LIKELIKE DISSOLVES LIKE
Non-PolarNon-Polar molecules molecules do NOT dissolve well.do NOT dissolve well. EX: OIL and WATEREX: OIL and WATER
http://www.worth1000.com/entries/85500/85693bHjg_w.jpg