Electricity & Magnetism, Hoover Dam, and 37 days left!

We just finished the Electricity Unit. I ended up being much simpler than I would usually choose to teach it, but my students had some really intelligent and in depth conversations about the content, so I can chalk it up to success!! Now we’re in the Magnetism Unit and since it is proficiency testing, AP testing, and a-million-and-one other approved school absences, I chose to make it rubric-based. They have a bunch of assignments and labs to complete before their test next week.

I showed my 9th graders the PBS American Experience documentary on the Hoover Dam this week and they were amazingly interested! It may have something to do with our school being 40 miles from the dam, but they had great questions and really interesting reactions to the working conditions, racism, etc. involved in the building of the dam. Can’t wait to show my physics students! Too bad there’s no chance of a field trip this year :(

Only 37 days left of the contract year! Woot! So much to get done, but it is time for the seniors to move on, underclassmen to move up, and teachers have a break from all of the above :)

Magnetism Unit

I’m working on developing a high school Physics magnetism unit. The lessons I’ve written so far are posted on the Lesson Plans page. So far, it consists of an introductory lesson, two lessons on magnetic fields, a computer-based lab connecting electricity and magnetism, as well as an end of unit project.

Since I am relocating to Las Vegas, NV, I am working to connect each of my lessons to the community. This unit easily demonstrates the science associated with the hydroelectric generators at the Hoover Dam. I can’t wait to bring students there for field trips!!

Chevy Volt

I’ve been seeing a lot of commercials for the Chevy Volt lately:

The one that plays on Hulu.com is only an animation of the number “230”, which is the estimated MPG for the Volt. I’ve been wondering how that’s possible, until I read a recent post by Dot Physics.

In “Chevy Voltology“, he goes into some detail about the specs of the Volt, as well as graphing the cars actual efficiency. You should check it out!

Other related posts are “The Law of Diminishing Returns, the Chevy Volt, gas milage, and hot air“, King of the Road writes a detailed evaluation of the Volt’s supposed efficiency and compares it to that of other small, fuel efficient cars.

On Good Math, Bad Math, author Matt writes a great post on how Chevy decided to use the “230 MPG” as part of their campaign and does the math to prove it. His post “The Chevy Volt gets 230 mpg? Only if you use bad math” was very clarifying!

This would be a great assignment for any physics class!

Electricity Producing Bugs!

I just found this really neat article about a bug that produces electricity as part of it’s digestion.

So cool – check it out!

Thomas Edison’s House and Laboratory

This weekend my husband and  I went to Thomas Edison’s estate Glenmont in West Orange, NJ. This was not his home when he invented electricity, but a massive laboratory sits at the bottom of the hill. The laboratory will reopen from renovations fall 2009. Here are some highlights of the afternoon, as well as a slide show of all our pictures at the end of the post.

Our picture just before the tour started.

The back of the house with the beautiful lawn.

The large porch lined with lights.

Edison’s Laboratory. We couldn’t go inside because of renovations, but it opens again in the Fall 2009.

Thomas Edison and his wife are both buried on the property.

To see other interesting parts of our visit (including a portrait of the Lord Kelvin), check out this slide show.

Mystery Circuit Box

I found an article about mystery circuit boxes several years ago in The Physics Teacher. I’ve recently had the opportunity to actually use it in a lesson!

Martha Lietz (the author of the lesson I based mine off of) uses rewired bathroom beauty bar lighting in order to teach her students about series and parallel circuits in reverse. Basically, students are given a strip of lights and unscrew the light bulbs one at a time to deduce how the circuit is wired.

I decided to take it one step further and use mystery circuits to assess students’ knowledge of circuits using various wirings of circuits in the different beauty bars in order to evaluate how well students understand the differences and effects of series and parallel wirings. You can view my lesson plan here.

One of the greatest parts of this demonstration is that the materials are easy to find and relatively inexpensive. I found the beauty bar at Lowes (or Home Depot) for around $13. I also had to by a wire cutter/stripper and extra wire nuts. Plus, you can use them over and over again!! I recommend using 40 watt rated bulbs or less because they get hot rather quickly.

One of my mystery circuits was the one designed by Lietz, and I’ve included pictures here. Can you figure out how it’s wired?

Picture One: All bulbs are screwed in tightly. Bulb one is the brightest, bulbs two and three are the dimmest but shine to the same intensity, and bulb four has a brightness right in the middle of the others. NOTE: It is important to be sure that a bulb’s brightness is due to the power it receives from the circuit and not simply a reflection of light from the bulb next to it. This was the major point of confusion for students with regards to bulb two.

 

Picture Two: Bulb one is unscrewed and all bulbs go out.

 

Picture Three: Bulb two is unscrewed. Bulbs one and two are the brightest and bulb three goes out.

 

Picture Four: Bulb three is unscrewed. Bulbs one and two are the brightest and bulb two goes out.

 

Picture Five: Bulb four is unscrewed. Bulb one dims slightly. Bulbs one, two, and three all shine at the same intensity.

 

Using the information and pictures provided above, can you figure out how the circuit is wired??

100th Post! Fun and Games…

I can’t believe I am at my 100th post already!! In honor of that, I’m sharing some really addicting, science related computer games I found lately.

Electric Box

I found Electric Box at Samgine.com and I was so excited when I realized it was a game all about creating circuits. In each level, the goal is to use the power supply (green button in the picture to the left) to cause the atomic picture to spin. In the case of Level 9 pictured here, I was given a water turbine, electric kettle, steam detector, magnet, IPS battery, and refrigerator in order to connect the power supply to the atomic symbol. The game is a great teaching tool, because it combines electricity, magnetism, mechanical energy, lasers, mirrors/reflection, and thermodynamics into one succinct circuit-related Physics computer game! All 14 levels are addicting and YouTube has walkthroughs available.

Bridge Craft

I found Bridge Craft on Candystand.com and it challenges the player to build bridges for the characters to cross using wood planks secured by steel and/or rope and confined by a budget. This would be a really neat game to use as a supplement to any sort of engineering, center of mass, or torque lectures. Some of the levels require extreme creativity since the challenges are not always simple and straightforward. The level pictured to the left was a bit troublesome for me because the ropes had to be just the right length, otherwise my bridge kept collapsing every time the little blue guy crossed! Walkthrough available on YouTube.

 

I hope you get a chance to play for a bit – happy 100th post!!!