Resistors in Series

Today we started dealing with more than one resistor at a time. First up: resistors in series. Homework is the front of Concept-Development 35-1. We'll do the back tomorrow.

Work Day: Electricity III

Today we just worked on Electricity III (below). I also printed out grade reports for you. If you get your grade report signed by a parent or guardian and then attach it to a late paper, I will waive the late penalty for that paper. It could also be a paper you have already turned in late and gotten back.

AC/DC

Today we talked briefly about alternating current and direct current, as well as the war between Thomas Edison and Nikola Tesla. We also watched the Epic Rap Battle of History between those two - one of the only ERBs that is school appropriate :)

Electrical Power

POWER! Homework tonight is Concept-Development 34-2.

Ohm's Law

Today we talked about the results of your lab as well as how voltage might affect current. Putting those ideas together gave us Ohm's Law. Your homework tonight is Ohm's Law.

Ohm's Law Lab - Take Two

Okay, let's try this again. Today you are completing a short lab to discover how resistance affects the current through a resistor. Your homework is to finish the analysis questions - you'll need graph paper!

Ohm's Law Lab - but Not Really

Only second period had class today. Just when third period was about to start, we had to evacuate for a bomb threat and eventually everyone went home. We'll try again tomorrow. Second period, you'll just have a free day tomorrow to allow the other classes to catch up.

Circuit Lab

Today we completed a qualitative lab to light a lightbulb using one wire and one battery. We compared all the ways that worked and found they all had two things in common (see bellwork - it ended up on the board). We also took some brief notes on circuit diagrams. Homework for the weekend is Concept-Development 34-1 (below).

Electrical Resistance

Today we talked about the factors that affect the resistance of a resistor. This involved us pretending to be electrons and running through the school. Homework tonight is Resistance.

Electric Current

Electric current! Homework is Electricity II.

There is a great xkcd comic about this last thing.

Flow of Charge/Voltage 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.

Electrostatics Test!

Test today! If you are absent, you need to make this test up within one week. There is an extra credit word find to work on after the test - no due date for that, but I will not leave it out for very long.

Electrostatics Study Guide

Today is your one day to work on the study guide. Abridged answers are below. Your test is Monday.

Faraday Cage and 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 2/8 until today for Conceptual and from 2/28 until today for Honors. Finally, we started work on your study guide. Tomorrow will be a work day and your test is on Monday.

Electric Potential/Voltage

Electric potential - also called voltage - is the last thing that will be on your next test. Homework is Voltage and is due tomorrow.

Coulomb's Law Practice

We only had 20 minute periods today, so all we did was practice some Coulomb's Law problems.

Electrostatic Potential Energy

Today we talked very briefly about electrical potential energy. No homework tonight.

Coulomb's Law

Today we used some fabricated data to derive Coulomb's Law. Your homework for the weekend is Concept-Development 32-1.

Practice: Electrostatics IV

First, we watched a demo and explained it for bellwork. A video of the demo and explanation is here, and a picture of the board at the end is below. Then we worked on Electrostatics IV, which is due tomorrow. There is a #7 on this assignment that does not show up in the link.

Charging by Induction

Today we did a silly activity to show charging by induction. Everyone was a proton or an electron in a conductor connected to the ground. I scared some of the electrons away into the ground with a negatively charged balloon to leave the conductor with a positive net charge. Then I attracted some electrons out of the ground into the conductor with positively charged candy, leaving the conductor with a negative net charge.

Homework tonight is Electrostatics III.

Polarization

Welcome back! In addition to the bellwork/notes below, we watched a demonstration of 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. Homework tonight is Electrostatics II.