Flow of Charge/Potential Difference

Today we begin our last unit: Electricity! We know that electricity is made of moving electrons, but what makes them move? It turns out all you need is a potential difference (voltage difference). When you don't have a potential difference, no charges flow and therefore there is no electricity. Watch this video of some kids touching an electric fence; until the last dude, all of those kids were at the same potential, insulated from a different potential (ground), so there was no electricity flowing through them.

Homework tonight is Electricity I - due tomorrow.

Study Guide Answers

Below you will find the abridged answers to the electrostatics study guide as well as a couple of problems we did together for bellwork.

Faraday Cages and Electrostatics Study Guide

Today we talked briefly about Faraday cages and why a car is a pretty good place to be during a lightning storm. We also watched a Top Gear video with a car being hit by lightning.


After that we counted and recorded your stamps from 2/6 until 3/24. Finally, we started work on your study guide. Thursday will be a work day and your test is on Friday.

Voltage and Electrical Potential Energy

First we compared gravitational potential energy to a new quantity, electrical potential energy.

Then we took some notes about electric potential, also known as voltage.

Your homework is Voltage.

Water Main Break

The water main broke sometime this morning, so we are releasing from school early. Period 1 got a lesson done today, but no one else, so today's lesson will just be Monday. Period 1 will probably go over Coulomb's Law on Monday since most of the class was gone last Tuesday.

Teacher Sick

I am home today, so you have a reading. There are two different readings, but you are only required to do one. If you do both you get extra credit.

Reading #1
Reading #2

Coulomb's Law

Today we derived Coulomb's Law by using an online simulation to collect data. Here is the lab:

Coulomb's Law Virtual Lab

We talked about the results of your lab to bring them together into Coulomb's Law, which we wrote on the board along with the bellwork from the beginning of class. It ended up being a little messy, but Coulomb's Law is in the top right corner area.

 Your homework is Concept-Development 32-1.

Practice: Electrostatics IV

Coming back from a three day weekend, I thought we could use some practice with what we've learned in this unit so far. So today we're just working on Electrostatics IV. Note that the last problem does not show up in the electronic copy; you must get a hard copy from school.

Work Day

Today is the last day of the quarter, so we have a work day. I hope you use your time well. Things you might want to do are:

• Turn in Electrostatics II and Electrostatics III
• Make up missing tests
• Make up missing work (especially labs)
• Make corrections on papers (especially labs)

Polarization and Induction

Bellwork first:

Then we read pages 389-392 in the textbook and took notes on:

• charging by contact
• charging by induction
• ground/grounding
• charge polarization/electrically polarized
• what's special about water?
• Why does a charged balloon stick to a wall?

You could have also worked on your homeworks as you read: Electrostatics II and Electrostatics III.

We then saw some demonstrations about stuff in your reading:

• A balloon attracting polar water molecules. A great video explanation (that I did not make) is here. You can do the same thing at home with a faucet turned very low and a plastic comb you have run through dry hair a few times.
• A charged balloon attracts and then repels paper pieces
• Students acting like electrons are repelled by a negatively charged balloon or attracted by positively charged candy to induce a charge on one side of the room.

 

Conservation of Charge and Charging By Friction

Homework: Electrostatics I

The picture above is almost the same bellwork and notes as today, just last year. I'm including it because today's is so dark and my iPod is still crashing when I try to edit:

Electrostatics Lab

Today I gave you some balloons and some rabbit fur and set you loose to answer these questions:

Ignore the date; I just used the picture from last year.

Quantum Test

Today is your test. As with all tests, if you missed it you have two weeks to make it up.

Spectrum Lab and Quantum Study Guide Answers

Today we completed the Spectrum Lab. If you missed it, you can either make it up at school or use the internet to figure out the two mystery elements. The elements we looked at were neon, hydrogen, mercury, nitrogen, oxygen, and helium.

You also had more time to work on your study guide; the answers are below. Sorry these are so dark; my photo editing app just keeps crashing.

Quantum Study Guide!

Time for a study guide! Half of the block period this week will be spent in lab and half on study guide work time, with your test on Thursday.

Conceptual Quantum Study Guide
Honors Quantum Study Guide