[new entry, 02 FEB 2009] From: Walter Sanford [mailto:wsanford@wsanford.com] Sent: Wednesday, January 21, 2009 12:24 PM To: David Venezky Subject: RE: Post-Lab Demos Hey Doc! Kelsie W. (4th per. Honors) asked me whether Gatorade energy drink would work as the electrolyte in a chemical wet cell (the product label uses the word "electrolyte"). I told her I didn't know, but we could test. Today she brought a bottle of "Gatorade G2" to class (from her lunch) and we tested the drink using a Cu/Mg pair of electrodes. Turns out it produced a voltage potential of ~1.5V and enough amperage to power the piezo buzzer. We also tested the motor/propeller but it didn't work. When we were finished testing, Kelsie said: "It's weird to think about drinking energy." Which leads to my question for you: Q. How does drinking something rich in electrolytes benefit the human body? When Kelsie first asked whether the drink would work as a chemical wet cell, kids asked a variation on my question and I had to be honest: I don't know! Thanks, Doc! A. http://en.wikipedia.org/wiki/Electrolyte -- > I wonder what the conductivity of the [G2] drink is. DV I don't know, Dave -- are you talking about the measurement in microsiemens from the bonding lab? I'll get some G2 from Kelsie next time I see her. WS > Next try the contents of a cheap soda as a wet cell. DV I tested 7-Up as electrolyte. I used Cu/Mg electrodes. Using the cheap-o analog volt- and amp meters, I got a reading of approx. 1 V; couldn't get a reading for amps. Nonetheless, the amperage was sufficient to power the piezo buzzer. Very cool! Any more suggestions? WS -- Date: Wed, 4 Feb 2009 15:04:05 -0500 (EST) Subject: Electrolyte Testing G2 sample, provided by Kelsie W. (first trial using "orange" color/flavor; more recent trial using "blue") G2 "blue": ~2,902 microsiemens 7-Up (soda): ~719-757 microsiemens (~avg. = ~738) == ViewDo: How to Make a Lemon Battery (Runtime = 04:41 min.) Cu = (+) Zn = (-) ions move from positive to negative (inside lemon cell); electrons move from negative to positive (along conducting pathway) wiring lemons in series: voltages add iPod: 33,000 lemons laptop PC: 650, 000 electric car: 60 million -- Ohm's Law (calculator) http://www.sengpielaudio.com/calculator-ohmslaw.htm V = R x I I = V / R R = V / I http://www.sengpielaudio.com/calculator-ohm.htm P = V x I <-- power = voltage x current Ohm's Law can be used to understand why lemon cells are able to run low-power devices only. == Google Search: "parts of a battery" [Note: ... a "battery" consists of a number of cells connected together.] Essential Parts, Chemical Wet Cell | Specific Materials ------------------------------------------------------- > Lemon Cell * container - lemon peel * electrolyte - lemon juice (citric acid) * electrode pair (different substances) - Mg/C, Cu/Mg, Zn/C, etc. * conducting pathway (e.g., copper wire) completes/closes the circuit, changing an open circuit to a closed circuit - e.g., test leads (a.k.a., "jumper leads") from voltage sensor, leads and either light bulb or motor/propeller ***Note: *Ions* migrate through the electrolyte; *electrons* flow along the conducting pathway (e.g., copper wire).*** ***Addtl. Note: Use Cu/Mg electrode pair to demo several low-power devices incl. calculator (formerly solar), blinking LED, and piezoelectric buzzer.*** > Test Tube Chemical Wet Cell * container - test tube * electrolyte - CuSO4 solution (a.k.a., "SmurfBerry Juice") * electrode pair (different substances) - ***Cu/Mg*** (or Cu/Zn) * conducting pathway (e.g., copper wire) completes/closes the circuit - e.g., test leads (a.k.a., "jumper leads") from voltage meter/probe, test leads and either light bulb or motor/propeller ***Note: Outside TTCWC (top of electrodes), Mg is the positive pole (black); Cu is the negative pole (red). Empirical Testing - 29 JAN 2007 TTCWC: ~1.2- to 1.5 V; ~420-440 mA (440 milliamperes = 0.44 amperes, that is slightly less than one-half an amp -- ~20x greater than the current generated by the lemon cell! For comparision, circuits in the home are 15 A.) [see full quote at end of file] "Typical LEDs, however, require 20 to 30 mA of current, regardless of their voltage requirements." -- [the following info rcvd. from DrV...] The currents we measured: Zn/Cu, 240 microamps [0.24 milliamperes]; Zn/C, 154 microamps [0.154 milliamperes]; Cu/Mg, 1970 microamps [1.97 milliamperes]; Mg/C, 770 microamps [0.77 milliamperes]. We must have tried several systems in Lemon vs lemon juice and 5% Citric Acid: Zn/Cu, lemon, 0.979 V, 240 microamps [0.24 milliamperes]; lemon juice, 0.986V, 850 microamps [0.85 milliamperes]; 5% Citric Acid, 0.993V, 1200 microamps [1.2 milliamperes]. [Note: the following part numbers may be incorrect...] The article about the Red blinking LED (276-036) and piezo buzzer, 3.5 kHz (273-060) were from Radio Shack. Best results were using Mg/Cu electrodes: 1.5-1.6V, 400 microamps with cells wired in series. [400 microamperes = 0.4 milliamperes] http://www.kpsec.freeuk.com/components/other.htm#buzzer "Buzzers have a voltage rating but it is only approximate, for example 6V and 12V buzzers can be used with a 9V supply. Their typical current is about 25mA. ... Buzzers and bleepers must be connected the right way round, their red lead is positive (+)." -- WtJ - Materials electrodes: zinc (2); copper (2); carbon (1); magnesium (1) [eight (8) possible combinations: ?2 x 2 x 2 = 8?] <-- ***research probability math*** See "Probability Central" http://ww2010.atmos.uiuc.edu/(Gh)/home.rxml -- Lemon Power - Project to Make a Battery From a Lemon [features definitions of the parts of a battery plus a simple discussion re: power (voltage) vs. current (amperage)] http://www.energyquest.ca.gov/projects/lemon.html [ca.gov = california] Dr. Dan's Homepage: The Official Lemon-Power Website! [features good examples of lemon-powered devices] http://members.aol.com/dswart/index.html FAQ About Food Batteries http://www.bluffton.edu/~bergerd/chem/food_batteries.html Volt http://en.wikipedia.org/wiki/Volt The volt (symbol: V) is the SI derived unit of electric potential difference. The number of volts is a measure of the strength of an electrical source in the sense of how much power is produced for a given current level. Ampere http://en.wikipedia.org/wiki/Ampere The ampere (symbol: A) is the SI base unit of electric current equal to .... Ohm's law http://en.wikipedia.org/wiki/Ohm%27s_Law The unit of resistance is the ohm, which is equal to one volt per ampere, or one volt-second per coulomb. The inverse of resistance, 1/R, is conductance, and its SI unit is the siemens (also unofficially called the mho). == Lemon Cell (Battery) http://www.hilaroad.com/camp/projects/lemon/lemon_battery.html "This is a single cell of a battery. The zinc nail and the copper penny are called electrodes. The lemon juice [citric acid] is called [the] electrolyte. All batteries have a "+" and "-" terminal. Electric current is a flow of atomic particles called electrons. Certain materials, called conductors, allow electrons to flow through them. Most metals (copper, iron) are good conductors of electricity. Electrons will flow from the "-" electrode of a battery, through a conductor, toward the "+" electrode of a battery. Volts (voltage) is a measure of the force moving the electrons. (High voltage is dangerous!)" Embedded links: - features link to nice video(s) of lemon-powered LED - table of potential voltages: http://www.hilaroad.com/camp/projects/lemon/electric_potential.html - voltaic cells: http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/electrochem.html Activity Extension: Hila Vinegar [Cell] Battery http://www.hilaroad.com/camp/projects/lemon/vinegar_battery.html == ***Note: Double-check possible error in TRG: Most reactive = Mg; Zn; least reactive = Cu.*** == > Post-Lab Demos: Lemon Battery "juicing" Radio Shack LED & buzzer Wire [at least] two (2) lemons in series [a battery]; use Mg/C electrode pairs. Connect cross-over cable between lemons (connect Mg & C electrodes); connect remaining electrodes to either LabPro sensor leads (volt- & amp meter). Measure/display voltage & amperage for lemon battery; voltage potential of the double-cell (~3.3-3.5 V; ? A) should be ~twice the voltage of a single cell (~1.5 V; ? A). Demo LED & buzzer. Notes: - *Ions* move between electrodes INSIDE the lemon cell; *electrons* move along the conducting pathway (i.e., the wires that complete the circuit). Metal electrodes vary in their ability to give & receive electrons. - Use a sharp knife to slice open the lemon in order to show discoloration caused by chemical reactions between citric acid and electrodes. Not all electrodes react with the citric acid. Observe hydrogen gas production (bubbling) around the point where Mg electrode is inserted in lemon. == (x) ***buy a multimeter (volts, amperes, etc.)*** SMS Volt meters: D.C. Volts (0-5 Volts, by 1s, increments 0.2s) SMS Amp meters: D.C. milliamps (0-500, by 100s, increments 20s Google Calculator: 500 milliamp = ? amp 500 milliampere = 0.5 ampere Google Calculator: 1 ampere = ? milliamp 1 ampere = 1 000 milliampere Google Calculator: 0.3 ampere = ? milliamp 0.3 ampere = 300 milliampere If a light bulb has a resistance of ~4.3 ohm, and is rated at 0.3 A, then a voltage of at least 1.29 V is req'd. to power the light bulb. == Activity Extension: "Test Tube Wet Cell" Materials: * test tube (container) plus two-hole rubber stopper (optional) * CuSO4 solution (electrolyte) * Mg & Cu strips (electrodes) * strip of blotter paper (separates half-cells) * connect the wet cell in a complete circuit (conducting pathway) with a light bulb and then a motor/propeller * photocopies, assessment activity - Demo - Assessment Activity (use as "open note" quiz) == Misc. Notes from: http://www.wsanford.com/~wsanford/gr8ps/01_green/ 00b_05-06_GSLG_Daily-Lesson-Planning.txt > "Where's the 'Juice'? Producing Electricity from Chemicals" - Do only Part 1: Lemon "Juice" [need either lemons or lemon juice] = Pre-Lab: [Mon., 13 DEC '04] - Battery vocabulary (***cross-reference w. both lab manual and lab manual test): * battery, electric: device that converts chemical energy into electrical energy * electrolyte: compounds that conduct an electric current in aqueous solution (or in the molten state). A ?nonmetallic? electric conductor in which current is carried by the movement of ions. [Gray area: Aren't either CuSO4 or NaCl-water "metallic" conductors?] * electrode: a conductor used to establish electrical contact with a nonmetallic part of a circuit anode: the positive terminal of an electrolytic cell cathode: the negative terminal of an electrolytic cell - Electricity Vocabulary: * circuit: the complete path of an electric current including usually the source of electric energy * voltage (volts): electric potential or potential difference expressed in volts * volt: the practical meter-kilogram-second unit of electrical potential difference and electromotive force equal to the difference of potential between two points in a conducting wire carrying a constant current of one ampere when the power dissipated between these two points is equal to one watt and equivalent to the potential difference across a resistance of one ohm when one ampere is flowing through it * amperage (amps): the strength of a current of electricity expressed in amperes * ampere: 1 : the practical meter-kilogram-second unit of electric current that is equivalent to a flow of one coulomb per second or to the steady current produced by one volt applied across a resistance of one ohm 2 : the base unit of electric current in the International System of Units that is equal to a constant current which when maintained in two straight parallel conductors of infinite length and negligible circular sections one meter apart in a vacuum produces between the conductors a force equal to 2 x 10^-7 newton per meter of length - Demo LabPro plus voltage probe. (x) Check storage rooms for simple stand-alone volt- and amp-meters. [Rm. 116 has at least one working pair.] (x) Check Rm. 116 storage cabinets for electrodes (metal rods). (x) ***Need to order carbon (C) rods and re-order Mg rods.*** = Lab Activity; answer summary questions, p. 64 (remaining 5-10 min.). Demo Cu/Zn electrode pair: Connect red lead to Cu; black lead to Zn (negative potential voltage). [Tue., 14 DEC '04] - Post-Lab Discussion: [Wed., 15 DEC '04] Question 2-4: Refer to Venezky's reference page from the "Handbook of Chemistry and Physics" (DV_The_Lemon_Cell.doc) Question No. 5. What clues did you observe that a chemical change took place in the lemon wet cell? Demo: Chemical wet cell using CuSO4 solution, Cu/Mg (or Cu/Zn) electrodes, small electric motor & propeller. Use smaller test tubes. Observe clues to chemical change (reaction): gas production (H?)(bubbling); color change; precipitate formation (demo Cu xls precipitate at bottom of test tube). Electroplate Zn electrode with Cu. ... or other electrolyte solutions, incl. salt water solution, vinegar, *citric acid solution*, etc. [Not likely to work, according to Dr. V. Need details.] == [addenda as of 25 JAN 2007; parse and move blocks of text to relevant sections, above] Hilaroad: Red lead from multimeter connects to positive (+) terminal of battery; black connects to negative (-) terminal. For a Cu/Zn electrode pair, Cu is the positive terminal. A multimeter also has two wires, one red (+) and one black (-), with metal tips. They are called probes. >> Use red & black Sharpies to mark positive (red) & negative (black) terminals on analog volt- and amp meters. electrons flow out negative terminal of battery; in positive terminal == [move to "Energy Transformations" lab activity] Note: Two or more interconnected PV modules create an array. > Wire solar panels in series; test to see if there is enough current to "power" flashlight bulb. YES! Photovoltaic cells rated for 0.5 V. [see sidebar notes, below] [mount solar panels on ring stand using test tube clamps] Five (5) solar panels = 2.5 V. (-)red[]black --> red[]black --> red[]black --> red[]black(+) Where: [] = solar panel == [misc. notes re: solar cell array] Subject: Solar Cell (fwd) [23 JAN 2007] [the following info printed on plastic packaging] [FCPS?] CAT#WL2148M-02 UM:EA SOLAR CELL .5V 500MA 3X1-7/8IN VEN# 3-500 -- 4-cell array, ~6" away from 150- to 200 W light bulb: +2.015 V (measured with Vernier Voltage Probe) 40 D.C. mA current (Google Calculator: 40 milliamperes = 0.04 amperes) In direct sunlight, solar array generated ~2.0 V and ~300 D.C. milliamps of current (0.3 A) [enough to power flashlight battery] == Now for some history: The Daniell Cell is named for John Frederic Daniell (1790-1845) who was an English chemist and physicist noted for electrical and meteorological investigations. The cell named after him was used in telegraphy and furnished 1.08 volt. It consisted of an amalgamated zinc electrode in dilute sulfuric acid (1:12 dilution of concentrated acid) and a copper electrode in saturated copper sulfate solution. In more recent time, any galvanic cell using the reaction: Zn + Cu++ --> Zn++ + Cu is called a Daniell cell. The two electrodes are separated by a porous partition that permits diffusion of ions between them. The cell that I demonstrate is close to the "Daniell Cell," but it does not have the porous partition between the electrodes. Similar to the original cell demonstrated by Daniell, it depends on the difference in densities of the Zn solution (0.01M) and Cu solution (1.0M) and is called a "Gravity Cell"! End of history lesson. Dave [Addenda: WBS] Cell Container: 250 mL beaker Electrolyte Solutions: CuSO4 (bottom); ZnSO4 (top) Electrode Pair: copper (bottom); zinc (top) Conducting Pathway: Vernier voltage probe + laptop/LCD; LED & buzzer (requires two cells wired in series) Set-up: Add ZnSO4 first (~100 mL, or enough to cover copper electrode); use small glass funnel (with cotton plug insert in order to enable slow flow of liquid) to add CuSO4 to bottom of beaker (enough to cover copper electrode, thereby raising liquid boundary layer midway between electrodes and also covering zinc electrode). Pre-Demo Demo: Insert copper electrode into ZnSO4; no reaction. Insert copper electrode into CuSO4; no reaction. Insert zinc electrode into ZnSO4; no reaction. Insert zinc electrode into CuSO4; zinc electrode is quickly plated with copper. If this happened in a battery, then the battery would quickly "go dead" because you would end up with two copper electrodes, which students should know will have no voltage potential. Main Demo Point(s) of Focus: > Difference in density enables one liquid to "float" on top of the other; > "Gravity Cell" clearly demonstrates (in clear glass beaker) what we are unable to observe through the opaque lemon peel -- the migration of ions in solution in the electrolyte! Post-Demo P.O.D.: Draw and label the essential parts of the "Gravity Cell" battery. The Cu electrode is positive; Zn electrode is negative. (Need to know in order to trace flow of electrons along conducting pathway.) Copper ions migrate (diffuse) upward into zinc sulfate solution; at least 12 hours before class, set-up a third cell used to illustrate this point. == Subject: Testing Circuits with a Multimeter - Show Direction of Electron Flow http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA8/SampleUseOfMovies/CJM/8_01_7_6_C_00_1a_.html A multimeter and a battery are used to show how positive and negative multimeter readings indicate the direction of electron current in a circuit. Discussion A digital multimeter can be used to determine the direction in which electrons move in an electrical circuit. Current and voltage readings are positive when electrons move from the negative multimeter jack through the multimeter to the positive multimeter jack. An AA battery has a (+) mark on the end that is positively charged and a (-) mark on the negative end. When the positive end and negative ends of the battery are connected through an electrical circuit, electrons move through the circuit from the negative end of the battery to the positive end. In this movie the multimeter is set to read DC voltage. When the red (positive) lead is connected to the positive jack of the multimeter and the positive end of the battery, and the black (negative) lead is connected to the negative jack of the multimeter and the negative end of the battery, the meter reading is positive -- electrons are moving through the multimeter from the negative jack to the positive jack. When the connections to the battery (but not to the multimeter) are reversed, the reading is negative -- the direction of electron flow is reversed. In the same way, when the multimeter is set to read current, a positive reading means electrons are moving through the multimeter from the negative jack to the positive jack, and a negative reading means electrons are moving in the opposite direction. == Subject: GE (Flash)Light Bulbs GE 222 (Flash)Light Bulbs 2.25V .25A/TL-3 Mini Screw Base Light Bulb Manufactured by: Eiko SKU 40492 Brand Eiko Volts 2.25 Base Miniature Screw Bulb TL-3 Filament C-2R Average Life (hours) 5 Boxed & Bulk Miniature Lamps MOD (Diameter) 0.38in/9.6mm == I ordered the Radio Shack multimeter. Is the red probe always positive and the black negative? Can I use the multimeter and red & black Sharpies to label the connectors on our analog volt- and amp meters so that the kids connect the test leads correctly (w/o having to reverse them)? If so, then how can I be sure I've labeled the terminals properly (Sharpies are permanent markers!)? Specific guidance is sincerely appreciated! WBS By convention, red is used for positive and black for negative. There's no difference at all between the probes electrically, of course. I presume the connectors on your existing meters are already labeled (but not color-coded), are they not? [Note: SMS analog volt- and amp meters are NOT labeled.] If not, the easiest way to figure it out is to use a battery to figure out the polarity, then mark the connectors appropriately. Phil Wherry == LEDs (20 matches) http://www.radioshack.com/search/index.jsp?kw=led&f=Taxonomy %2FRSK%2F2032298&categoryId=2032298&kwCatId=2032058&cp=2032058.2032233 [buy THIS one!] 5mm Red Blinking LED $1.39 Model: 276-036 Catalog #: 276-036 For use with your electronic projects. Use with digital clocks and remotes. Typical MCD is 3.5. This 5mm Red Blinking LED has a typical wavelength of 697mm. Size is T-1 3/4 or 5mm Red lens color Viewing angle is 30° 90mA (max) Typical Voltage is 2.25, with a maximum voltage of 2.6V Comes as package of 1 What's in the box 5mm Red Blinking LED (1) [sidebar] Note: "MCD" refers to "luminous intensity." Google Search: luminous intensity (MCD) http://www.gizmology.net/LEDs.htm "The brightness of LEDs is measured in millicandela (mcd), or thousandths of a candela. Indicator LEDs are typically in the 50 mcd range; "ultra-bright" LEDs can reach 15,000 mcd...." "As a rule of thumb, different color LEDs require different forward voltages to operate - red LEDs take the least, and as the color moves up the color spectrum toward blue, the voltage requirement increases. Typically, a red LED requires about 2 volts, while blue LEDs require around 4 volts. Typical LEDs, however, require 20 to 30 mA of current, regardless of their voltage requirements." -- We found 15 matches for "buzzer" in Component parts. Search all product information for more results. http://www.radioshack.com/search/index.jsp?kw=buzzer&f=Taxonomy% 2FRSK%2F2032230&cp=2032058&kwCatId=2032058&categoryId=2032230&fbc=1&f= PAD%2FProduct+Type%2FBuzzer&fbn=Type%2FBuzzer [buy THIS one!] PC-Board 12VDC 70dB Piezo Buzzer $3.29 Model: 273-074 Catalog #: 273-074 Make some noise. Save space with this 70dB mini Piezo PC-mountable buzzer. Mounts easily to your PC and operates on 12VDC. Carries a 7mA current at 12V Rated at 4,200 Hz What's in the box 1 x 70dB PC Piezo Buzzer (Operates on 12VDC, carrying 7mA current at 12V. Buzzer rated at 4,200Hz) Note: Range of human hearing: 20 - 20,000 Hz. The hertz (symbol: Hz) is the SI unit of frequency. One hertz simply means "one cycle per second"; 100 Hz means "one hundred cycles per second", and so on.