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Warm Up:
Write 10 facts you already know about water.
Water Unit
What is WATER?
Water is a molecule
It is also a compound. Why? What makes is a compound?
The word water usually refers to water in its liquid state.
What is WATER?
What is WATER?Pure water has NO smell or taste,
and a pH of 7 so it is not acidic or basic
That makes it NEUTRAL
Structure of Water
One water molecule is:
Two hydrogen atoms (H2) chemically bonded to one oxygen atom (O)
Structure of Water
Hydrogen ends are slightly more positive.
Oxygen end is slightly more negative. This means that
water is a polar molecule
WHY?????
Models of Water Molecules
Let’s let TED explain it!
Properties of Water
Water has four properties that make it unique.
1. Cohesion
2. Adhesion
3. Capillary Action
4. Universal Solvent
Cohesion is when water molecules stick to other water molecules (attract each other like magnets)
Cohesion at the surface of water is called surface tension.
SURFACE TENSION PICS
More SURFACE TENSION PICS
Surface Tension – Cohesion at the surface creates a thin “skin” on the water.
More SURFACE TENSION PICS
Adhesionis when water molecules stick to other materials
Dew
–w
ater
dro
pson
a s
pide
r’s
web
.
Capillary ActionWhen a liquid moves
up very narrow tubes because of cohesion and adhesion against gravity.
Ex: plants bring water
up through their roots to their stems and leaves
Capillary ActionA meniscus is when
the liquid “climbs” the sides of a graduated cylinder.
glass su
rface
Water in Space
Universal SolventWater’s polarity gives it the ability to dissolve many different substances.
Almost every substance can dissolve in water over time.
Universal Solvent
Almost…
3 StatesWater is the only substance on Earth that commonly exists in all 3 states.
Liquid – WaterSolid – IceGas – Water Vapor
Changing States
Water can easily move between its three different states through several natural processes
WATER
Another way of looking at changes in state!
Websites from the Presentation
1. http://www.brainpop.com/science/earthsystem/water/2. http://ed.ted.com/lessons/how-polarity-makes-water-behave-strangely-christina-kleinberg3. http://www.youtube.com/watch?v=oAY3yISf-24
Other cool water related videos
4. http://www.surfline.com/video/premium-partner-video/rubber-souls-new-zealand_103895(Surfing)
5. https://www.youtube.com/watch?v=BickMFHAZR0(Capillary action in trees)
6. https://www.youtube.com/watch?v=ph8xusY3GTM(Super-cooled water)
7. https://www.youtube.com/watch?v=D-wxnID2q4A(Walking on water – sort of!)
