Define these terms:

-electron affinity

-insulator

-conductor

-Coulomb

-polarization

-charging by friction 

Discuss:

Air is a better insulator than water. How could you use this in building a really efficient house?

Discuss what happens to the electron cloud as an atom becomes polarized.

Water molecules have a polar covalent bond. What does this mean and how does it affect polarization?

I rub a balloon on my hair. I have put it next to a wall and it sticks. The wall or the balloon: Which is ionized? Which is polarized? How can you tell?

_________________________

Write (type/print) the answers out. Turn it in. Rock and roll. 

1. During a physics lab, a plastic strip was rubbed with cotton and became positively charged. The correct explanation for why the plastic strip becomes positively charged is that ...

b. the plastic strip acquired extra protons during the charging process.

c. protons were created as the result of the charging process.

d. the plastic strip lost electrons to the cotton during the charging process.

2. Saran Wrap has a larger electron affinity than Nylon. If Nylon is rubbed against Saran Wrap, which would end up with the excess negative charge? ____________ Explain.

3. A physics teacher rubs a glass object and a felt cloth together and the glass becomes positively charged. Which of the following statements are true? Circle all that apply.

b. The felt became charged negatively during this rubbing process.

c. Charge is created during the rubbing process; it is grabbed by the more charge-hungry object.

d. If the glass acquired a charge of +5 units, then the felt acquires a charge of -5 units.

e. This event violates the law of conservation of charge.

f. Electrons are transferred from glass to felt; protons are transferred from felt to glass.

g. Once charged in this manner, the glass object and the felt cloth should attract each other.

h. In general, glass materials must have a greater affinity for electrons than felt materials.

4. Which statement best explains why a rubber rod becomes negatively charged when rubbed with fur?

a. The rubber which the rod is made of is a better insulator than fur.

b. The fur is a better insulator than the rubber.

c. Molecules in the rubber rod have a stronger attraction for electrons than the molecules in the fur.

d. Molecules in the fur have a stronger attraction for electrons than the molecules in the rubber rod.

Back to the Physics classroom.

I'll be hit and miss for here on out... giving, proctoring subject area and AP test. So... we'll mix robotics and electricity from here on out.

I'm here today so I'm going to lecture (fun, fun).

Let's read about the fundamentals of electricity.  Lesson One

Today review basic concepts in part one and two of lesson one. This is basic stuff you should know but review it anyway. There's always one or two things in there to learn. Hey, ABBIE... please do the math on part 2 question 7 and be prepared to discuss it.

Once done with that, REALLY read part 3 on Charge Interactions. Read it! Don't scan it... I said don't scan it... reeeaaaaadddd it!

Okay. As normal do all the questions.

Rock on.

Amen.

Here's the board for our wave discussion. Maybe it'll help. Click on the image to download large image.

Lecturing today on the Electromagnetic Spectrum. Just for those who are not here today.... look it up... Get to class... Now! 

Electricity... ah... ah... ahh.... (say it melodically).

I don't know a lot about this, so we'll learn together. 

What I do know is that when the lights go out, everybody gnashes their teeth and flex their corrigated supercilli. 

We're going to spend a while on this so get yourself motivated. 

For today: 

Using online sources find the following:

• What is electricity?

• What are the different types of current? What's the difference in AC/DC? What about static?
  

• What's a transformer?

• How do we produce electricity?

Also... research some on these guys...  

• Edison

• Tesla

• Westinghouse

What were their dreams of distributing electricity? 

Test tomorrow...

That's right. Test... on three days worth of material. What will be on the test? Simple machines, compound machines, and computing mechanical advantage.

What's on tap today? A lab on computing MA of simple machines.  Going back to EdHead (odd machine) to play with the Compound Machinces section and maybe even a practice test.

Let's do it.

You will have a pop test in 10 minutes on the relationship of the 11th dimension and the unification of the string theory. Make sure you understand the connection between the big bang and the oscillation of matter membranes. You will also need to create a universe in your basement.

Hope you're having a good April Fool's day...

On to Mechanical Advantage. Yesterday we introduced the 6 (7) simple machines which include three classes of levers, two types of pulleys, screw, inclined plane, wedge, and the trusty wheel and axle.

Today we'll jump into a little math. It can get rather ugly from a simple start but we'll try to stay pretty ;)

Your assignment:

• Using web resources, look for mathematical computations of MA... both simple and the more complex. Work out how these computations may be applied to all six simple machines.
• On a piece of paper, draw a grid with three columns.
• In the first column list the simple machines.
• In the second, describe a situation for using the simple machine... example: I use a 10 foot lever with a fulcrum placed 1 foot from the end to raise a 100 pound weight.
• In the third, appropriately compute the MA of the situation. From the example above, I would say: The length of the force end of the lever is 9ft from the fulcrum position. The length of the load (resistance) end of the lever is 1ft from the fulcrum. In this situation you could figure the MA by dividing 9/1 which, of course, equal 9. Your MA = 9.
• Turn the paper in. Yeah. Real class work... such a long forgotten thing in the world of 212.

Here are the links to test your knowledge about simple machines. You need sound for the Edhead site. Do these in order...

Simple Machines Flash

Do all three links at the bottom... "Essences... Finding... and Putting to work" 

Edheads

Fun Flash interactive site.

Have some fun.

Rube Goldberg made a living poking a little fun at technology by coming up with insanely complex machines to accomplish simple task. All these machines were a combination of simple machines sprinkled with zany bits and pieces of situational and slapstick humor.

As an introduction to simple machines, take a look at Mr. Goldberg's contraptions.

When your done analyzing this machines, let's get a little more serious. Here's your assignments:

• Using internet resources, identify 6 simple machines and their uses.
• What is mechanical advantage and how do you compute it.
• Come back at the end lesson for some fun sites to test your knowledge.

I'll post those test links by the end of class.