Ø 2 Hydrogen atoms + 1 Oxygen atom -> H2O
+ + - -
- + +
2 Hydrogen atoms -- --
- 8+ 8n
1 Oxygen atom -- --
2.polar – has charged areas
(hydrogen side positive,
oxygen side negative)
3.Opposite ends attract – water molecules
try to stick together
II. Properties of Water
Ø Capillary action – water molecules are
attracted to each other & surrounding
• “Wick” away moisture
a) Cohesion – like molecules stick
together (ex: raindrops)
b) Adhesion – unlike molecules stick
together (ex: raindrops cling to a line)
2. Surface tension
• Tight surface of water
• Caused by polar molecules pulling on
3. Universal Solvent
• Water dissolves many substances
• Solution – mixture formed when one
substance dissolves in another
• Solvent – substance that does the
4. High Specific Heat
• Amount of heat needed to
increase the temperature of a substance
• High because water is polar
• Water takes longer to heat up or cool down
III. Changing State
Ø States of Matter:
a) Solid – close molecules, rigid structure (ice)
b) Liquid – molecules move freely, take shape of
c) Gas – molecules move very freely,
spread out (water vapor)
2. Evaporation - Change from liquid to gas
3. Condensation – Change from gas to liquid
4. Freezing – Change from liquid to solid
5. Melting – Change from solid to liquid
1) A water molecule is made up of
a.two hydrogen atoms bonded to an oxygen
b.two hydrogen atoms bonded together.
c.two oxygen atoms bonded to a hydrogen
d.two oxygen atoms bonded together.
2) Because water consists of polar
a.most of it is found at the North and South
b.water molecules tend to stick together.
c.it falls as sleet or snow when temperatures
d.it can be attracted using a magnet.
3) Tightness across the surface of
water that is caused by polar
molecules pulling on each other is
4) Water is often called the universal solvent
a.it can cling to the fibers of paper and cloth.
b.it dissolves so many substances.
c.it exists in all three states on Earth.
d.its frozen form floats on its liquid form.
5) Water is the only substance on
a.commonly exists in all of its different
b.freezes at very low temperatures.
c.boils at very high temperatures.
d.exists in the liquid state.
6) The process by which a gas
changes into a liquid is called
Experiment with Water Properties
Ø Pick a water property to Available Materials
experiment with. Observe your • Dropper
property in action. • Water
Ø What happens normally? • Penny
Ø Is there any way to affect what • Soap
happens? • Salt
Ø Write a paragraph about what • Graduated cylinder
you observed. • Straw
Properties • Food coloring
• Capillary action • Pepper
• Adhesion • String
• Cohesion • Paper towels
• Surface tension • Wax paper
• Universal solvent • ?? (Ask if I have it)
Example Experiments with Water Properties
• Follow that String (p. 49)
• How many drops of water fit on the side of a
penny? (p. 51)
• What effect does soap have on the surface
tension of water?
• Can you prevent a meniscus from forming on a
• How many coins can you fit into a full glass of
• Will a pin float on top of water?