Practice AP Test

For the rest of the week we are taking, then grading, a practice AP test. I am not allowed to give you this test to take home, so your only opportunity to look at it is IN CLASS.

Even if you are not taking the AP test next week, this practice test will be useful to focus your studies for the semester final.

Electricity Test

Today is your last unit test. Next week we will be taking a practice AP exam, so you may want to review material over the weekend.

AC/DC and More Practice

We talked for 5-10 minutes about the difference between alternating current (AC) and direct current (DC). There's a great explanation on MIT's Ask and Engineer.


The rest of the time was yours to continue preparing for your test tomorrow. See yesterday's blog entry for the practice test and solutions.

Electricity Practice Test

Today we started working on the practice test:

Electricity Practice Test

There is an abbreviated solutions key here and solutions videos below:

#1
#3
#4
#6
#7/#8 (formatting issue; these are the same problem)

I also passed out missing assignment reports.

Practicing Compound Circuits

A lot of you were gone on Friday so today was another work day. You had two goals:

I will NOT be collecting or grading the book problems; just read through them and do whichever ones with shich you feel you need practice.

Using Systems of Equations to Solve Compound Circuits

Today we looked at a way to solve circuits using systems of equations. Basically you use the Junction Rule and the Loop Rule until you have the same number of equations and unknowns, then solve the system of equations.

Officially your homework is the worksheet Compound Circuits Practice, but most of you finished that in class. I also put out a Ranking Task worksheet that I was going to give you next week. Email miss.volkening@gmail.com for PDF scans of any worksheets.

Solving Compound Circuits

How do you solve a circuit that has both series and parallel components? That was the topic today. We took notes by solving a problem on the board. Here is the problem before any work was done:

Here is a video that I made a couple of years ago solving this problem.

And here is the problem after it was solved:

Homework toight is the worksheet called 35-2, although some of you may have also started the worksheet Compound Circuits Practice which is what we'll be working on tomorrow. Email miss.volkening@gmail.com for PDF scans of worksheets.

Circuit Breakers

For bellwork today we asked which would cook faster: three hot dogs wired in series or three hot dogs wired in parallel? Then we tried it out. The answer was the parallel hot dogs because the power is greater (resistance is lower so current is higher).

We then talked briefly about circuit breakers, why we have them, and how they work. If you missed this the easiest way to get the information is to read section 18.6 in the textbook.

Homework tonight is Ch.18 (p.644) #37, 38, 40.

Series and Parallel Circuits

I hope you did your homework reading, because today we jumped right into solving series and parallel circuits. First we did one of each on the board (picture below) and I showed you trick involving color-coding equipotential lines. Then we used the worksheet Concept-Development 35-1 to practice in groups, and finally you practiced individually with the worksheet Series and Parallel Circuits (which is homework). Email miss.volkening@gmail.com for PDF scans of either worksheet.

Circuit Lab #3: Intro to Parallel and Series Circuits

Today you completed a qualitative lab to introduce us to series and parallel circuits:

Circuit Lab #3

You may also be able to complete this lab with the online simulator PhET Circuit Construction Kit.

Homework for the weekend is to read and take notes on sections 18.1, 18.2, and 18.3.

Electrical Power

When current flows through a resistor, the resistor converts electrical energy into other forms of energy. The rate at which this conversion happens is the electrical power. Below are some short notes that ended up on the whiteboard.

We then completed a worksheet in class (email miss.volkening@gmail.com for a copy) and started homework:

Ch. 17 (p.612) #33, 34, 44

Ohm's Law

Today we used your lab results to come up with Ohm's Law (picture below). This equation can be applied to any individual component of a circuit, the circuit as a whole, or anything in between. Basically we're going to be using his a lot.

The rest of the period we just practiced various Ohm's Law problems. Whatever you didn't finish in class is homework:

Ch. 17 (p. 611) #10, 11, 13, 15, 20, 51

Circuit Labs #1 & #2

Today we first went over the symbols used in circuit diagrams as bellwork:

Bellwork/Notes: Circuit Diagrams

Then we completed Circuit Lab #1 and Circuit Lab #2. Both need to be completed in your lab notebook and only checked, not turned in. You may also finish at home and have them checked Wednesday.

Circuit Lab #1

Purpose: Find 4 different arrangements of a single bulb, single battery, and single wire that result in a lit bulb.

The following needs to be in your lab notebook:
Sketches or circuit diagrams of every arrangement you try, even the ones that don't work.
Answers to the following:What do the arrangements that worked have in common? What do the arrangements that didn't work have in common?

Caution: some arrangements may result in rapid overheating. If an arrangement gets hot, STOP IMMEDIATELY. Lighting the bulb and getting hot are mutually exclusive arrangements, so just holding onto a overheating arrangement in the hope that it will start to work eventually is not a smart idea.

You may also be able to complete this lab with the online simulator PhET Circuit Construction Kit.

Circuit Lab #2

Purpose: Find the relationship between voltage difference, resistance, and current in a circuit.
Materials: resistors of various value, battery, wire/alligator clips, ammeter (measures current).

The following needs to be in your notebook:
A brief procedure for taking data
Data table
Graph (linearized if necessary)
Slope calculation
Speculation on what the slope represents
Final equation using proper variables (not x and y)
Description of one error and how it could be reduced/eliminated.

You can also use the online simulator PhET: Ohm's Law to take data at home to complete this lab.

You also have homework tonight: a worksheet titled "Concept-Development 34-1" on the front and some hand-drawn diagrams on the back. This again contains copyrighted material, so I cannot post it here, but email me at miss.volkening@gmail.com and I will email you back a scanned PDF.

Electrical Resistance

Today's topic was electric resistance:

Notes: Electrical Resistance

Homework is Ch. 17 (p.609) Multiple Choice #3, 4, &14 + Problems #14 & 16

Electric Current

Today we started our last unit (all about electricity and simple circuits) with electric current.

Notes: Electric Current

Homework tonight is Ch. 17 (p. 610) Conceptual #3 and Problem #1