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Water!. Marine Science 2010. Why Water is Your Friend…. Water has several properties which make life possible Transparency Cohesion & Adhesion Temperature buffer Solvent ability. Covalent Bonds. In covalent bonds, atoms share electrons Vs. ionic where electrons are stolen.
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Water! Marine Science 2010
Why Water is Your Friend… • Water has several properties which make life possible • Transparency • Cohesion & Adhesion • Temperature buffer • Solvent ability
Covalent Bonds • In covalent bonds, atoms share electrons • Vs. ionic where electrons are stolen
Unique Properties: Bonding • An H2O molecule consists of 2 H atoms and 1 O atom covalently bonded together. • Our Moon orbits Earth, simply because Earth has more mass, thus more gravitational pull. • Now, apply that same concept to H2O: All the electrons orbit oxygen since it has more mass.
Hydrogen Bonds • So, since the water molecule has a negative and a positive end, it is called a polar molecule. • Since opposite charges attract, water will also bond with itself. This is called a hydrogen bond
Polarity Leads to More Unique Properties… • Cohesion • Adhesion • High Heat Capacity • Density • Solvent Ability
Cohesion • Water’s tendency to stick to itself • Ex: surface tension
Adhesion • Water’s tendency to stick to other materials • Ex: the meniscus • Ex: capillary action
Heat Capacity • It takes a lot of energy to raise or lower the temp. of water • Water resists temperature change • Helps moderate climates • Allows organisms to maintain homeostasis
H2O as a Temp Buffer • Water’s temp buffering effect causes the oceans to be a stable environment • Very important for the early evolution of life when conditions on land were severe and ever-changing
Ice & Life • Ice is less dense than liquid water; it floats. • If it sank, lakes and oceans would freeze solid, and early life, existing totally within them, would have been extinguished.
Ice Fishing • While not crucial to life, ice fishing is a recreation enjoyed by millions. • It can be dangerous, however, and should be attempted with great caution. • http://www.youtube.com/watch?v=3zf-a5AD7gM
The Universal Solvent • Because of its polarity, water’s charged areas can pull apart ionic or polar compounds