“Did you know that dolphins are so smart that within a few weeks of captivity they can train people to stand on the very edge of the pool and throw them fish?” THE SOLUTION TO SOLUTIONS

 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 CONDUCTIVITY – 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 CONDUCTIVITY – 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. ELECTRICAL CONDUCTIVITY – NOTES

1. Create your new Notebook header & update TOC. THE SOLUTION TO SOLUTIONS 2. Find the Key Idea in the Chapter Organizer (p. 100) and write it in your notebook.

 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? INTRODUCTION

 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.instrumentelectric chargemeasuring instrumentWilliam Gilbert 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 chargeselectrical charge  Example: VOCABULARY  Conduction: the flow of electrical charge in an objectelectrical charge  Example:

 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. CONCEPT

 Electroscope  Styrofoam Cup electroscope  Water Demonstration  Paper DEMONSTRATIONS

 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? ELECTROSCOPE

 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. PAPER

 Does water have a charge?  Does water attract or repel other charged objects?  Predict how a charged plastic knife will affect 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 affect 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. WATER DEMO

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.

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) TASKS TO BE COMPLETED DURING CLASS TODAY!

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 )  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.

 Read “Other Polar Covalent Molecules” on p  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 ) RESOLVING DISSOLVING

NOTES

 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? PREVIOUSLY WE…

Human Hands Most Positive Asbestos Rabbit Fur Glass Mica Human Hair Nylon Wool Fur Lead Silk Aluminum Paper Cotton Zero Steel Wood 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 TRIBOELECTRIC SERIES (GROUPING MATERIAL ACCORDING TO THEIR TENDENCY TO GIVE UP THEIR ELECTRONS

 Write and/or draw a picture: What do you know about the following items? If you do not know anything about it, write IDK ACTIVITY – 5 MINUTES  Proton  Neutron  Electron  Nucleus  Shell  S shell  P shell  Ion  Bohr Model  Rutherford Experiment  Covalent Bonds  Ionic Bonds  James Bond