Properties of Water

1
Properties of Water
2
Cohesion and Adhesion

• Cohesion
• Water is attracted to other
• water
• Surface tension for water striders

• Adhesion
• Water can also be attracted to other materials
• Meniscus in a graduated cylinder

http//www.mtbaker.wednet.edu/harmony/ditch/water_
strider.htm
http//en.wikipedia.org/wiki/Meniscus
3
Surface tension

• What if the paper clip were turned the other way?

4
Water is unique

• Only natural substance that is found in all three
  states at the temperatures normally found on
  Earth.
• liquid, solid (ice), and gas (steam)
• Earth's water is constantly interacting,
  changing, and in movement.

5
Specific Heat Capacity

• The amount of heat required to raise the
  temperature of one gram of a substance one degree
  Celsius.
• Specific heat capacity of (in J/gC)
• Water 4.18
• Dry air 1.00
• Wet mud 2.51
• Brick 0.84

Waters high specific heat capacity means it can
absorb a lot of heat before it starts to get hot.
6
Something to think about

• A scientist has kept track of weather and
  temperatures for a number of years. On March
  15th 2004 there is no snow or ice on the ground
  in Halifax. On March 15th 2005, there is snow
  and ice on the ground in Halifax. If the sun is
  reaching the earths atmosphere and Halifax at
  the same rate on both dates (presuming both days
  have clear blue skies), which date will the
  temperature seem warmer? Why?

7
Water and changing seasons

• In the spring, the suns energy is used to melt
  remaining snow and ice so the temperature does
  not rise as much as it does in the absence of
  snow and ice.
• In the fall the sun provides less heat than it
  does in the summer. However, as water freezes,
  it releases heat and the temperature does not
  drop as fast as it would if there were no water
  to freeze.

8
Water and climate

• If you live on the coast, are your winters going
  to be more or less mild than if you live on the
  prairies? Why?