Why Ice Floats

1
Why Ice Floats

• Q. Imagine a frozen lake in winter. Is there
  anything living in this lake during wintertime?
• A. A variety of things fish, turtles, many
  different plants.

2
Why Ice Floats

• Q. What would happen to these organisms if ice
  were more dense than liquid water?
• The ice would sink as it formed instead of
  forming a protective shield for the organisms in
  the water below.
• http//ed.ted.com/lessons/why-does-ice-float-in-wa
  ter-george-zaidan-and-charles-morton

3
Why Ice Floats

• Frozen water and liquid water have the same mass
  BUT the water takes up more space as ice than it
  did as a liquid. (due to the gridlike crystal
  structure)
• This means that ice is less dense than liquid
  water.
• Iced tea!

4
Specific Heat

• Specific heat is the amount of heat needed to
  increase the temperature of a certain mass of a
  substance by 1 C.
• Water has an unusually high specific heat which
  means that it requires a lot of heat to increase
  its temperature.

5
Think about this

• On a hot July day, the air, sidewalk, and sandy
  beach are HOT! But if you jump into a pool or
  the ocean the water is cool.
• If you were to go for a swim at night, the water
  is warm compared to the cool air.
• Why does this happen?

6
Because

• In the summer, the suns heat warms the land more
  quickly than the water. The warm land heats the
  air above it.
• Remember that it takes more heat to increase the
  temperature of the water.
• At night, the land/air cools off faster than the
  water does.

7
Words Worth Knowing (ISN 39)

• Polar molecule
• Surface tension
• Capillary action
• Solution

• Solvent
• Evaporation
• Condensation
• Specific heat