Electricity

Reproduction Unit | Space Unit | Electricity Unit | Chemistry Unit

 * 2014 April 7: Static Electricty and Introduction**

Electrical Quantities - Definitions from class today:
 * **charge (Q)**: electrons are negative charges, protons are positive charges. Charge is related to mass (charges are to electricity like mass is to matter). Measured in coulombs (C).
 * **current (I)**: flow of charges (size of the water hose is an analogy). Measured in amps (A).
 * **voltage (V)**: the amount of energy per charge (energy normalised to charge kind of like why we work out marks in percents - it's easier to understand) Water analogy,voltage is the pressure. Measured in volts (V).
 * **power (P)**: rate (per sec) of using energy. Measured in watts (W).
 * **resistance (R)**: opposite of conductance. How a material opposes flow of charge. Measured in ohms (Ω)
 * **energy (E)**: exists in different forms (heat, sound, light). Energy allows you to do work (turn a turbine etc). Measured in joules (J).

We will be solving equations this unit: V=IR P = Energy/Time P=IV V = E/Q I = Q/t

P=I 2 R (if you want to go beyond what we need to do)

Use this PhET simulation to demonstrate these three laws.
 * Charge** **(pg 205-209)**
 * Atoms are neutral** -same # of protons (+) as electrons (-)
 * Charged object:** -either more protons than electrons (+ charge) or more electrons than protons (- charge) (Page 208 of your text)
 * Laws of charges (page 209)**
 * opposite charges attract ( +,-)
 * like charges repel (+,+) or (-,-)
 * charged objects (either + or -) are attracted to neutral objects


 * What use is static electricity? (pg 227-231)**
 * industrial [|spray painting] Neutral metal being painted with charged paint
 * [|photocopier]
 * electrostatic furnace filter (paper with metal wire grid)
 * [|inkjet printer]
 * [|Industrial chimney]
 * What are some problems? (page 225)**
 * sparks can start a fire at the gas pump
 * static sensitive electronic parts (eg computer chips)
 * lightening is natural static electricity


 * Table 6.2: Tribolectric Series (page 208)**
 * do checkpoint page 209
 * Page 211 some questions to do.


 * 2014 April 10:** Charging by Contact and Charging by Induction

Here is the data for the two labs which have a first due date of Monday, April 14: Charge by contact (page 221): @http://youtu.be/MQV8S7TxG3Q Refer to page 215 and 216 media type="custom" key="25619718" Charge by induction (page 222): @http://youtu.be/U_loBKLToD4  Refer to page 217 media type="custom" key="25619730" The ebonite (black plastic) rod doesn't work very well. I asked you to substitute the clear plastic rod (acetate) instead as it is also in the negative region of the tribolectric series (page 208).

Some things to note:
 * Why do we use a glass rod and an acetate rod as our knowns (why do we know what the charge is of these two materials when we rub it with the other material)?
 * Why would it not make sense to use wood as one of our knowns?

Labs on pages 221 and 222 are due April 14 (1st due date)

If you stay up tonight, the [|lunar eclipse] will be great to view at about 1 AM SK Time (morning of April 15). We will work on metric conversions and if you need, wrap up the labs page 221-222 and hand it in.
 * 2014 April 14 **



media type="custom" key="25643352"
 * 2014 April 15:** I managed to [|capture some images and video] of the lunar eclipse. The clouds broke long enough for me to observe something!


 * 2014 April 16:** Went over the static labs pages 221-222 which have a final due date of May 5.

How do you use a wire, a battery (or electric power source) and a compass to detect electric current? media type="custom" key="25656160" media type="custom" key="25656138"


 * 2014 April 28:** Worked on observing magnetic effect when electric current passes through a coil of wire. We found that when a metal rod is inserted inside the coil, the magnetic effect is stronger.


 * 2014 April 30:** Work on take home question for the next test. (CLICK HERE)


 * 2014 May 5:** Static Lab due today, working on circuits with PhET


 * 2014 May 7-8:** Series and Parallel Circuits

Videos you can use to do this lab [|Two bulbs the same, one different] [|Three bulbs the same] [|Two bulbs the same] media type="custom" key="25982598" media type="custom" key="25982602" media type="custom" key="25982604" Here is a file that can be loaded into the [|PhET DC Circuit construction kit]: Here are videos you can use as data for the Parallel Circuit lab from Page 257: [|Three bulbs in parallel] [|Two bulbs in parallel] media type="custom" key="25982606" media type="custom" key="25982608"
 * Series Circuit Lab page 256.** You can use these videos if you didn't get the data: Also, you can use the [|DC Circuit Construction Kit] from PhET to do this lab virtually too.
 * Parallel Circuit Lab Page 257:**

Page 256 # 11: load is the lamp. They are asking what’s the difference between a series circuit with 2 lamps versus 3 lamps Page 257 #10c: change voltage to current

Checkpoint:
 * 1) Which type of circuit is a voltage splitter (series or parallel).
 * 2) Which type of circuit is a current splitter (series or parallel).

The two labs (Page 256-257) are due on May 12th (first due date).

If you are done the lab, do the following:
 * Read page 250-252
 * Do page 253 (all questions).


 * 2014 May 12:** Circuit Labs First due date today.
 * Do the questions on page 253 (refer to page 250-252).
 * Do practice problems page 260-261 (the small boxes beside each of the examples)
 * Do Checkpoint 7.3 page 264.
 * Don't forget your Take Home Question

Electrical Energy Consumption (page 286): do learning checkpoint Efficiency (page 287): do practice #1-3 Checkpoint page 290 #2, 3,
 * 2014 May 21:**

Large scale generating systems (page 272, Figure 8.5)
 * Transformers help convert high voltage to low voltage and vice versa.
 * Using the [|PhET generator demo], it can be shown that you get a higher voltage when you have more coils of wire.
 * P = IV (power = current x voltage).
 * At the generator, the transformer converts the __voltage from the generator to a__ voltage to the transmission lines.
 * At the other end (your home), the transformer converts the __voltage from the transmission lines to a__ voltage to your home
 * Which side of the transformer would have more coils (high voltage or low voltage)


 * Appliance || Power Rating || Time Used || Energy Used (kWh) ||
 * Toaster || 2000 W = kW || 15 min = hours ||  ||
 * AC || 10 kW || 10 hours ||  ||
 * clock radio || 2 W || 24 hours ||  ||


 * 2014 May 28:** Review today and tomorrow.