Transcript Properties of Water Part 3

Water Temperature Lab
Create two graphs similar to
this
100
Temperature (oC)
75
50
25
0
5
10
15
Time (minutes)
20
25
30
Hypotheses
• What will temperature graph look like from freezing
water to boiling?
– Why?
• What will temperature graph look like for tap water
versus salt water?
– Why?
• What will temperature graph look like for tap water
versus sugar water?
– Why?
• Of salt water and sugar water, which will boil fastest
and why?
• Will the ice to steam, salt water, and sugar water
mixtures boil at the same temperature? Why or why
not?
Materials
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Note paper, pencil
Hot plate
Beaker
Thermometer
Jar (for measuring)
Ice
salt (NaCl)
Sugar (C12H22O11)
Procedure
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In groups of 2
Pick a lab table
Gather materials
Turn on hot plate
Part 1:
– Fill beaker with ice
• Add water to fill line and place on hot plate
– Record initial temperature then rerecord every 30 seconds until
boiling
• Part 2:
– Add salt then water to fill line
– Record initial temperature then rerecord every 30 seconds until
boiling
• Part 3:
– Add sugar then water to fill line
– Record initial temperature then rerecord every 30 seconds until
boiling
Post Lab
• Did all three of your graphs look the
same?
• Which mixture boiled the fastest?
• Which boiled at the lowest
temperature?
• Are your numbers the same as the
other table group’s?
Salt vs. Sugar
• Phase Changes
• You Tube Video
• Boiling tap water versus salt water
Properties of Water III
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Discovery and Origin
Human Body and Functions
Chemical Make Up
A Few Property Refreshers (and some I
missed the first time)
– Universal Solvent
– Capillarity
– Pressure
Discovery
• Henry Cavendish
– “Discovered” water in 1784
– Was the first to synthesize water by
combining oxygen (dephlogisticated
air) and hydrogen (inflammable air)
• Antoine Lavoiser
– Father of modern chemistry
– Coined the term hydrogen which
means “water former”
Origin
• Earth started as a red hot ball of burning
liquids and gasses.
• When they cooled they formed a solid crust
of rock
• Then…
– Hot gasses from the core were released through
volcanoes and geysers to form our atmosphere
– Comets from outer space are believed to have
additional water to Earth since even if our
atmosphere was 100% water vapor (it is only
• Pangea
• Water makes up about 75% of Earth’s surface
• Most abundant compound in nearly all living
things
Human Body
• First nine months of life spent in water (amniotic sac)
• Amounts in humans:
• Newborn baby: 78% water
• Adults: 50-75% water (difference between muscles
and lower bone density in older females)
• Lungs: 90% water
• Blood: 82% water
• Skin: 80 % water
• Muscle: 75% water
• Brain: 70 % water
• Bones: 22 % water
• Other things:
• Jellyfish: 95% water
• Dog: 70% water
Human Body
• Functions
– sweat cools body and gets rid of
waste
– tears keep eyes clean
– lymph fluid flushes out bacteria
and germs
– saliva breaks food down for
digestion
– blood carries oxygen and food to
cells and waste away from the
cells
– water filled Kidneys filter blood
– water lubricates muscles so they
can move
Chemical Make Up Composition
• Two parts Hydrogen
• One part Oxygen
Chemical Make Up - Polarity
• Hydrogen is positively charged (+)
• Oxygen is negatively charge (-)
– When water bonds to anything it orients based on their
charges
• Water molecules attract or are attracted to other polar
molecules
• Oil is non-polar and so does not mix with water
Simpler View of Water Molecule
H
H
Positive charge
near Hydrogens
Negative charge
near Oxygen
O
Properties - Pressure
• 1 cubic foot of water weighs 62.5
pounds
• Water Pressure animation
• Water pressure can be deadly
Properties – Universal Solvent
• Because of it’s polarity, “+” and “-” ends allow it to
bond easily with other molecules
• Examples:
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water dissolves minerals in the soil for plants to use
gasses such as oxygen for fish to breathe
air born chemicals that form acid rain
water dissolves some types of rock like limestone
• Stalactites- hang from ceiling
• Stalagmites- grow from the cave floor up
– Both are formed by minerals left behind by the evaporated water.
Properties – Capillary Action
• This property allows plants to soak up
water through its roots
– A 60m tree soaks up about 4 bath tubs
worth of water per day
• Water moves against gravity through
tubes or capillaries
• Walking water
Water Property Summary
• Water: Liquid Awesome Crash Course