Transcript Properties of Water - Johnston County Schools

Unique
Properties of
Water
Mrs. McAven
8th Grade Science
Riverwood Middle School
The Properties of Water
CH.2 section 1
• Read pgs. 46-51
• On page 51 answer #’s 1-3 (ALL) in complete
sentences.
CH. 2 section 2
• Read pgs. 52-57
• On page 57 answer #’s 1-2 (ALL) in complete
sentences.
Properties of Water
What are some characteristics that make you different
from everybody else? Maybe you can play basketball
really well, or have a freckle on the tip of your elbow, or
maybe you can draw better than anybody else you know.
It may seem strange, but each substance in the world has
special characteristics that make it different from every
other substance. Just like you, they have characteristics,
or properties, that make them unique. Believe it or not,
water has some of the most unique properties of all!
VOGO
Side 1
Side 2
WORD
• Definition
• Example/Sentence
• Picture
Words:
Adhesion
Buoyancy
Capillary Action
Cohesion
Where can I find these words?
Chapter 2 (pg. 44)
Density
Polarity
Specific Heat
Surface Tension
Universal Solvent
ADHESION
Definition:
• the ability of water molecules to attract to other
substances.
• Because water molecules are polar (having one positive end
and one negative end) they attract other substances.
Example:
• raindrops sticking to a window or glass
• water sticking to paper towel
BUOYANCY
Definition:
• the ability of an object to float in water.
Example:
• floating in the ocean or a pool
• a boat
CAPILLARY ACTION
Definition:
• the process that moves water through a
narrow porous space
Example:
• water moving up a straw
• water moving up a plant stem
COHESION
Definition:
• the ability of water molecules to attract
towards each other.
– Because water molecules are polar (having one
positive end and one negative end), they attract
each other.
Example:
• water “dome”
• rain drops
DENSITY
Definition:
• the measure of mass of a substance per unit
volume
Example:
• ice floating on water
POLARITY
Definition:
• when one molecule has opposite charges on each
of its ends (one end is slightly positive, the other
end is slightly negative).
Example:
Water (H2O) is a polar molecule because its hydrogen end is
slightly positive and its oxygen end is slightly negative.
SPECIFIC HEAT
• The amount of energy it takes to raise the
temperature of a substance by one degree
Celsius
• Water has a very high specific heat.
• This means that compared to other substances, it takes a big change in
energy to change the temperature of water.
• Example: The ocean does not drastically
change temp.
SURFACE TENSION
Definition:
• the force that acts on the particles at the
surface of a material
Example:
• Water striders (bugs)
• painful belly flop
UNIVERSAL SOLVENT
• Water is called the “universal solvent”
Definition:
• this means that water can dissolve more things than any
other substance.
Example:
• water can dissolve: soap, sugar, salt, toothpaste, baking
soda, etc.
Acting it out
• Students will be divided into pairs.
• Each pair will be given one of the properties of
water to “act out.”
Words:
Adhesion
Buoyancy
Capillary Action
Cohesion
Density
Polarity
Specific Heat
Surface Tension
Universal Solvent
Assessment Statements
1. The water is sticking to the side of the glass.
adhesion
2. Water droplets combine together in the atmosphere to
make rain drops.
cohesion
3. Salt dissolves in water.
universal solvent
4. When I dropped a rock in the river, it sank.
buoyancy
5. On the coast in the summer, the ocean takes a lot longer
to heat up than the air and land.
specific heat
6. Water molecules have a positive end and a negative end.
polarity
Water Properties Practice
1.
2.
The suction cup will only stick to the window if I wet it first.
My mom used water to make Gatorade for the team. All of the
powder dissolved completely in water.
3. Water striders are able to walk on water without sinking.
4. I tried to mix the oil with the water, but no matter what I did the
two liquids would not mix.
5. The window was covered in rain. As the rain ran down the window,
the drops came together to make larger drops of water.
6. Gina’s doctor suggested that she join a water aerobics class for
exercise to keep from re-injuring her knee. He told her that the
water takes the pressure off of her knee.
7. The paper towel soaked up the spill in a jiffy.
8. The log floated down the river.
9. The blue dye in the water traveled up to the petals of the white
flower.
10. An iceberg floats on water in the Artic.
Unique Properties of Water
Mini Labs
1.
2.
3.
4.
5.
Sink’n Lincoln
Water bug
Water Rope
Iceberg
Shipwreck
Sink’n Lincoln
1. Predict how many drops of water you
can fit on a penny.
2. What was the actual number of drops
you could fit on the penny?
3. What property of water allowed you
to fit that many drops on the penny?
Water bug
4. A paper clip is not lighter than water,
yet it can stay on top of the water. Explain
why this is.
5. Explain what the soap did to the
surface tension of the water.
Water Rope
6. What is capillary action? How does this
help plants?
Iceberg
7. Why does ice float on top of water?
8. Rank the densities of the liquids from
most dense to least dense.
9. If water’s density is 1.0 g/mL, what can
be determined about the other liquids’
densities in the column?
Ship Wreck
10. Does the density of the boat
affect the buoyancy?
How Stuff Works: WATER
1.What is a dipole? How does water’s dipole molecular
structure affect its properties?
2.Why is water essential to life on earth? Why do scientists
credit water with allowing life to form?
3.How do plants transport water from the roots to the
leaves?
4.How does the Hoover Dam generate electricity? What are
the environmental drawbacks of damming a river?
5.Why does water resist compression?
6.What is cloud seeding? How does cloud seeding encourage
rainfall?