Homework from last class:• Complete the 7-2C lab activity worksheet (if not

already completed in class)

• Complete the “Neutral, Positive, or Negative Charges?” and “Positive, Negative, and Neutral Objects” worksheets

• Study for Ch. 7 quiz next class

• Read over class notes and check class bloghttp://www.msoonscience.blogspot.com

Chapter 7 Quiz•You will have ~15 minutes to write the quiz.

•Please fill in the Scantron form with your name, date, block, and quiz VERSION number.

•Do NOT write on the quiz – only the answers on the Scantron form will be marked.

Good luck!

Chapter 8 pp. 270-275

Ch. 8.1 Electric Potential Energy and Voltage

What do the following have in common?

They all require batteries to operate!

Good detective work!

Demo Time!

What is a battery?Energy: the ability to do work – to make things move or

change

A battery is a device that stores the energy in electric charges so that it can be used at some point to do work.

• A battery is a source of electric potential energy

Electric potential energy: stored energy that has the potential to make something move or change

pp. 270 - 271

A battery converts chemical energy electrical energyEx: Batteries that power a flashlight• Batteries are also called electrochemical cells• May be dry cells or wet cells

pp. 270 - 271

What does a battery do?

Moist paste

Fluid

pp. 270 - 271

Terminals (aka electrodes): the end points of a battery where we make a connection

• Electrodes are in a moist paste called an electrolyte conducts electricity

• Electrons build up on one side (negative)

• Electrons withdraw from the other side (positive)Once +ve and –ve charges are separated, they have the ability to do workEx: Making a bulb light up

Electric Potential DifferencePotential difference (aka voltage): the difference in potential energy

(stored energy) per coulomb of charge between two points of an electric circuit.

• Unit for voltage is the volt (V)• Measure voltage with a voltmeter• Voltage causes charges to move – charges (extra

electrons) will move from a higher level of energy to a lower level of energy

pp. 272 - 273

• Voltage is produced when electrodes in an electrolyte chemically react to produce electrons and different charges on each electrode.

• Creates a potential difference.

Homework for next class:• Complete the Reading Check questions on p. 275 (#s 1-

9)• Complete the “Reading an Analogue Meter” worksheet• Bring a fruit for the next class! We’re doing a fruit lab!• 5 bonus marks if you bring your own fruit!

• Examples: grapefruit, orange, lime, lemon (relatively large)

• Read over class notes and check class bloghttp://www.msoonscience.blogspot.com

Have a great weekend!

Works CitedImages taken from the following sources:http://cobygz.en.made-in-china.com/product/DqvENnjVhQiP/China-Portable-MP3-CD-Player-with-Am-FM-Stereo-Tuner-MP-CD451-.htmlhttp://www.binbin.net/compare/Control-A-Kid-Remote.htmhttp://www.mrgadget.com.au/blogarchive/2004_12_01_mrgadgetblog_archive.htmlhttp://5-h.wikispaces.com/Science+Spothttp://www.itechnews.net/2007/09/09/casio-exilim-ex-z8-digital-camera/http://www.geeky-gadgets.com/spy-gadgets-the-video-camera-watch/http://www.teach-nology.com/worksheets/early_childhood/color/detective/http://icydk.com/2007/09/22/ozzy-osbourne-the-new-energizer-bunny/http://mtbethel.blogs.com/greenwald/20082009/page/7/http://www.123rf.com/photo_7187238_yellow-small-battery-with-positive-and-

negative-signs.htmlhttp://classroomclipart.com/cgi-bin/kids/imageFolio.cgi?

action=view&link=Clipart/Animated_Clipart&image=lightbulb.gif&img=&tthttp://www.saltysmarine.com/index.php?main_page=index&cPath=84_120_116http://www.foodsubs.com/Fruitcit.html