On Target? Do this on your Warm Up worksheet! Why do you think the chemicals with the formula that looked like “C_H_O_” had similar conductivities and melting points? Explain your answer.

For today 1.Warmup 2.Categorizing substances follow-up 3.Electroscope intro Objective: I can use my macroscopic observations to determine what is happening to objects on a microscopic level.

Look at Properties Data From Last Week What properties do you think are most important for categorizing the chemicals?

Notes! Write in Your Lab Notebook Groups of chemical compounds share macroscopic similarities – Many hard, crystalline solids with high melting points do not conduct electricity as solids, but do conduct electricity when dissolved in deionized water – Medium-hard, powdery substances with low melting points sometimes dissolve in water partially, but conduct electricity poorly, if they do at all What is causing this on the microscopic level? Electricity is involved (Charges)!

Electroscope

Make a Data Table in Your Lab Notebook MaterialPredictionObservationWhy do you think this happens? Plastic knife Glass rod Wood Stick Balloon Your choice

Make a Data Table in Your Lab Notebook

Observe and Write in Your Lab Notebook: How do charged objects (plastic knife, glass rod, balloon) react with the tiny paper bits? Did all of them move toward the balloon? What does this tell you about the charge of the paper

What Do You Remember About Static Electricity? What is static electricity? Opposites attract! Like charges repel, and opposite charges attract Does it matter which object is positive and which one is negative? – No!

Exit Ticket Assignment ObjectWhat I observed macroscopically (drawing or words) What it means microscopically (drawing!) Electroscope with plastic knife Electroscope with glass rod Paper bits with balloon Use sketches to help explain what is happening microscopically. You should use the words conduction, positive charge, negative charge, repel, and attract.

EXIT TICKET- ANALOGY The water molecule is like a compass needle because______….. Paper bits are like IONS because______….

2-Question Exit Ticket-EXPLAIN Describe what is happening microscopically as the pin moves when it is brought close to the plastic knife* *Use the words conduction, charge and repel or attract. You can draw a picture if you like! CONDUCTION = to move or transfer charge from one place to another. Metals are good conductors because they move charge from one place to another. Describe why the balloon picks up some of the paper, but not all of the paper* *Again, use the words conduction, charge and repel or attract. You can draw a picture if you like!

pg. 115 (1-5)

What about paper? How does a charges plastic knife interact with tiny paper confetti? Charged glass? What I sawWhat it means microscopically

What about water? Predict how a charged plastic knife will affect a stream of water. Does water have a charge? Does it attract or repel other charges objects? Look again at the diagram on pg. 113.

Sketch Diagrams to Explain Sketch a microscopic view of a stream of water falling past a charged plastic knife and a charged piece of glass. Use + and - symbols for charges.

Possible sketches

pg