THE SOLUTION TO
SOLUTIONS
“Did you know
that dolphins
are so smar t
that within a
few weeks of
captivity they
can train
people to stand
on the ver y
edge of the
pool and throw
them fish?”
ELECTRICAL CONDUCTIVIT Y – NOTES
 Materials that allow an electric current to flow are conductors
 Metals are good conductors
 Materials that do not allow electric current to flow are
insulators.
 Rubber is a good insulator
 Electrical Conductivity is a physical property that involves the
flow of electrical charges through a solid or liquid
 Electric Current is the flow of charges
ELECTRICAL CONDUCTIVIT Y – NOTES
 A Conductivity Meter is a tool that measures electrical
conductivity.
 Has 2 probes that are not connected which prevents the flow of
charges.
 For the electric current to flow, you need to make a connection
between the 2 probes.
 If the probes are placed in contact with a conductive material, the
charges are able to flow and the light goes on.
 If the probes are placed in contact with an insulator the charges are
unable to flow.
 For electric current to flow, there also must be movement of electric
charges. A conductor provides the charged particles and the pathway
for them to move.
ELECTRICAL CONDUCTIVIT Y – NOTES
All metals are conductors.
Conductors can also work through the movement of ions.
Ions are charged particles.
Batteries work through the movement of ions.
Substances that produce ions in water solution are
electrolytes.
 These substances do not conduct an electric current as solids
because their ions are not free to move about in a solid.
 When the substance dissolves in water, the ions are free to
move about, which constitutes the current.
 Electrolytes can vary in the degree to which they conduct
current.
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THE SOLUTION TO
SOLUTIONS
1. Create
your new
Notebook
header &
update
TOC.
2. Find the
Key Idea in
the Chapter
Organizer (p.
100) and
write it in
your
notebook.
INTRODUCTION
 Read Intro to The Solution to Solutions P. 111 – 113. Take
note of the pictures and captions.
 Previously we grouped things into categories based on
macroscopic observations
 Hard, crystalline solids with high melting points do not conduct
electricity as solids, but do conduct electricity when dissolved in
water
 Powdery substances with medium melting points conduct little or no
electricity, but are soluble in water.
 Soft, oily materials with low melting points do not conduct electricity
and are not soluble in water.
 What’s happening on a microscopic level to explain what we
see at the macroscopic level?
VOCABULARY
 Electroscope:
 An electroscope is instrument that is used to detect electric charge
on a body. It was the first electrical measuring instrument. The first
electroscope was invented by British physician William Gilbert around
1600.
VOCABULARY
 At the atomic level, charge is due to the sum of positive and
negative particles composing an object. An electrically
neutral object has the same number of positive and negative
charges.
 The ability to charge an object depends on the ability of the
material to attract or give up electrons.
VOCABULARY
 Electrostatic Induction: redistribution of electrical charge in
an object, caused by the influence of nearby charges
 Example:
 Conduction: the flow of electrical charge in an object
 Example:
CONCEPT
 Charging by friction: separating positive and negative
charge by rubbing two different materials together
 Since the two objects are made of different materials,
their atoms will hold onto their electrons with different
strengths.
 As they pass over each other the electrons with weaker
bonds are “ripped” off of that material and collect on the
other material.
 The material that “donates” the electrons becomes
positive, and the material that “accepts” the electrons
becomes negative.
DEMONSTRATIONS
 Electroscope
 Styrofoam Cup electroscope
 Water Demonstration
 Paper
ELECTROSCOPE
 Predict what will happen when:
 A charged knife is brought close to the 1 st charged pin.
 A charged glass stirring rod is brought close to the 2 nd charged pin.
 A charged glass stirring rod is brought close to the 1 st charged pin.
 What did the electroscope demonstrate about charges on the
knife and glass?
PAPER
 Cut Paper into small bits.
 Carefully observe the paper bits while a charged plastic knife
is brought close to them. What happens?
 In your science notebook write down what you observe
macroscopically.
 Write what you think it means microscopically.
 Carefully observe the paper bits while a charged glass rod is
brought close to them. What happens?
 In your science notebook write down what you observe
macroscopically.
 Write what you think it means microscopically.
WATER DEMO
 Does water have a charge?
 Does water attract or repel other charged objects?
 Predict how a charged plastic knife will af fect the stream of
water macroscopically. Record your prediction in your
notebook.
 Sketch what you think is happening microscopically.
 Observe what happens when a charged plastic knife is
brought close to a stream of water.
 Predict how a charged glass rod will af fect the stream of
water macroscopically. Record your prediction in your
notebook.
 Sketch what you think is happening microscopically.
 Observe what happens when a charged glass rod is brought
close to a stream of water.
WUZ UP?
 The electrical nature of matter?
 This helps us explain solubility.
 And it helps us explain the formation of compounds
which can be then be grouped into categories.
TASKS TO BE COMPLETED DURING CLASS
TODAY!
In your notebook, write Stop and Think. Answer the following
questions:
 1: How did the electroscope demonstrate how (+) and (-)
charges interact with each other ?
 2. How does the separation distance affect the amount of force
a charged object can exert on another charged object?
 3. What happened at the microscopic level for the plastic knife
and glass to begin the demonstration neutral and then acquire a
charge?
 4. Is “neutral” a third type of charge? Why ?
 5. Does paper exhibit both plus and minus charges ? Explain.
 Answer Stop & Think Part II (p. 116)
 Answer Stop & Think Part III (p. 118)
THE SOLUTION TO
SOLUTIONS
PART IV: RESOLVING DISSOLVING
 Create a sub-heading in your notebook “Part IV: Resolving
Dissolving
 Create a T-Table to take notes on the reading assignment
 “Fact or Idea” on one side
 “Questions I have about the fact or idea” on the other side
 Read Solvation Process (p. 120 -122)
 Work within your table group to answer any of your questions in your T table.
 Make sure to update your vocab section with new vocabulary words that
you find in the reading
 Using your knowledge of covalent and polar molecules from the
reading, draw a series of sketches that show why water does not
dissolve paraffin.
 Include + and - symbols where appropriate.
 Explain each sketch with a caption.
RESOLVING DISSOLVING
 Read “Other Polar Covalent Molecules” on p. 123 -124.
 Keep a T-table with notes.
 Work within your table group to answer any of your questions in your
T-table.
 Make sure to update your vocab section with new vocabulary words
that you find in the reading
 Using your knowledge of covalent and polar molecules from
the reading, draw a series of sketches that show why
molecules such as sugar are soluble in water.
 Include + and - symbols where appropriate.
 Explain each sketch with a caption.
 Complete Reflect & Connect (p. 124 -125)
NOTES
PREVIOUSLY WE…
 Grouped things into catagories based on macroscopic
observations
 Hard, crystalline solids with high melting points do not conduct
electricity as solids, but do conduct electricity when dissolved in
water
 Soft, oily materials with low melting points do not conduct electricity
and are not soluble in water.
 What’s happening on a microscopic level to explain what we
see at the macroscopic level?
TRIBOELECTRIC SERIES
( G R O U P I N G M AT E R I A L AC C O R D I N G T O T H E I R T E N D E N C Y T O G I V E
UP THEIR ELECTRONS
Human Hands
Asbestos
Rabbit Fur
Glass
Mica
Human Hair
Nylon
Wool
Fur
Lead
Silk
Aluminum
Paper
Cotton
Steel
Wood
Most Positive
Zero
Amber
Sealing Wax
Hard Rubber
Nickel, Copper
Brass, Silver
Gold, Platinum
Sulfur
Acetate, Rayon
Polyester
Styrene (Styrofoam)
Saran Wrap
Polypropylene (Thermal clothing)
Vinyl (PVC)
Silicon
Teflon
Most Negative
ACTIVIT Y – 5 MINUTES
 Write and/or draw a picture: What do you know about the
following items? If you do not know anything about it, write IDK
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Proton
Neutron
Electron
Nucleus
Shell
S shell
P shell
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Ion
Bohr Model
Rutherford Experiment
Covalent Bonds
Ionic Bonds
James Bond