Date: Sun, 6 Feb 2005 14:10:17 -0500 (EST) Subject: Daily Lesson Planning - Gr8PS Scope & Sequence - GSLG & YSLG > Student Info [1 day, Advisory schedule] > Syllabus [1-2 days, Advisory schedule] > Observation & Inference Demos: "All Billiard Balls are Striped" (located in Science Olympiad storeroom) & Bottle Ba-Whoosh!; magic tricks &/or optical illusions [1 day] Bottle Ba-Whoosh! Add ~25ml rubbing alcohol to a 5gal. H2O bottle. Cover with inverted 250ml beaker. Coat insides of bottle with excess liquid before igniting vapor. > Metric System, incl. interrelationship among length, volume, & mass GSLG ---- > Characteristic Properties: Density "How Tightly Packed? Determining Density" Do only Part 2: Determining the Identity of a Solid, pp. 12-16 (small cube of Al, two medium cubes of Al, and three larger cylinders of Al) [several days] "Density Dilemnas - Density Practice Problems" pp. 17-18. == * Google search re: "characteristic property" + matter - http://www.sirinet.net/~jgjohnso/matter.html - http://homepage.mac.com/dtrapp/PhysicalScience/lab3_4.html (Archimedes) - http://www.thesciencedesk.com/studyguidedensity.htm Study Guide: Density - http://jeffcoweb.jeffco.k12.co.us/isu/science/IPS/Big%20Ideas.html - http://www.sasked.gov.sk.ca/docs/physics/u6a3phy.html Honors: "... have students obtain mass and volume data for a given substance [Al]. Develop a mass versus volume graph. Determine the density of the object from the slope of the graph." [1 day] == > Density demos: "party" bubbles (CO2) & flaming bubbles (methane); Coke + Diet Coke cans; Bill Nye "Buoyancy" + Will It Float? (Letterman video segment + sack o' balls & alcohol/ice) [1 day] Density Demo: Floating ["Party"] Bubbles on "bed" of CO2 in aquarium, produced by either of the following reactions: Alka Seltzer + water --> CO2 or the netralization reaction (acid + base) ... vinegar + sodium bicarbonate (baking soda) --> water + salt + CO2 C2H4O2 + NaHCO3 --> HOH + ?salt? + CO2 "Household Vinegar is about 3% acetic acid and 97% water (with a mixture of a small amount of a few other chemicals). Acetic acid has the formula C2H4O2. So acetic acid has the elements Carbon (C), Hydrogen (H), and Oxygen (0). Baking Soda is called Sodium Hydrogen Carbonate or Sodium BiCarbonate. The formula is NaHCO3 giving it Sodium (Na, latin for Natrium), Hydrogen (H), Carbon (C), and Oxygen (O)." [UIUC] > Density Quiz: Part I - Multiple Choice [1 day]; Part II - Lab Practicum (using lead sinkers) [1 day] Pre-lab: show "Energy" Bill Nye video (from "Heat/Energy" videotape, SMS Library) > Law(s) of Conservation of Mass & Energy (a theme of the course): "Energy Transformations" (Chains) lab activity [~1.5 days]; post-lab discussion [~.5 day] > Background: Physical- vs. Chemical Change - Solutions & Solubility: Background reading, textbook [20 min.]; "Disappearing Crystals - Experimenting with Solutions" pp. 19-22 EDD [20 min.] - "Disappearing Xls" lab activity [1 day]; G/T-Honors enrichment activity(ies), incl. xl systems & growing xls [1-2 days]. - "Solubility and Temperature" gizmo, www.explorelearning.com (Gr8 Physical Science/Chemistry). Collect data [1 day]; graph data using Logger Pro [1 day]. - "Finding Solutions" p. 23 > "Chemical Detective - Finding Evidence of Chemical Change" lab activity - pre-lab physical- & chemical change demos: * H2O + CaCl2 --> exothermic reaction * PbNO3 + KI --> precipitate * vinegar + baking soda --> gas production - flasks: use wooden splints to test gas formed in flasks: [1 day] H2O + Alka Seltzer --> CO2(gas) + ? ... and ... Hydrogen peroxide + yeast --> O2 (oxygen gas) + ? - Post-Lab Discussion > Post-Lab Demo: Catalysts - Chem. reaction that produces hydrogen gas: Zn + H2SO4 + catalyst (CuSO4 solution) --> H(gas) + ? ["Squeeky the Chihuahua" or "Pop goes the Chihuahua." See e-mail notes for details re: demo and chem. equation.] When flame-testing the gas inside the test tube, be sure to hold the test tube vertically with the flame near the bottom of the tube. - "Old Foamey" - ChemFax!, Flinn Scientific Inc. [See "Old_Foamey.pdf"] - Bill Nye video(s): "Phases of Matter" (26 min.); and ***"Chemical Reactions"*** (26 min.) > Sidebar: Intro. "The Atom Project" assignment, incl. Bohr model of atom. [~1 day] > The Atom Project - Library research: hardcopy & digital resources (online) [1 day] www.chemicalelements.com www.chemicool.com www.webelements.com - Mobile Lab: "Discover the Elements - The Interactive Periodic Table of the Elements" CD-ROM (icon on desktop) [1 day] - ?Foldables instead of poster? - Presentations (emphasize structure of atom, info. re: Periodic Table). Grade projects using rubric during presentations. [~2 days] > "The Invisible Atom," pp. 31-34. Use for drill & practice. Modify directions; use 6-panel sheet for drawing Bohr models. [1 day for activity; 1/2 day for review.] > "Endo- and Exo-: The Reaction Twins," (Measuring Temperature Changes) pp. 45-49 [1 day + ~1/2- to 3/4-day review (VERY TIGHT SCHEDULE!)] Employ student leadership model: 1-2 Lead Teachnologist(s); 1-2 Lead Scientist(s), by reaction: No. 1 = citric acid + sodium bicarbonate (baking soda); No. 2 = HCl(aq) + Mg. Review procedure the day before lab. Circle appropriate reaction on graph titles. ***Post-lab demo: Flame test CO2 produced by reaction of citric acid + sodium bicarbonate; allow students to touch outside of flask. Optional: Demo instant ice- and heat packs, e.g., ThermaCare heat wraps, Ace cold packs, etc. ***Need explanation of where energy goes during endothermic reactions.*** Preparation & Provisioning: Reaction 1: 30 ml citric acid solution (+ 10.0 g baking soda) 2 formulae: FCPS Tchr's Resource Guide - 1.5M citric acid solution: add 315 g of citric acid to 1 L of water Dr. Dave's recipe - [advantage being Dr. V's recipe fits in a 1L flask] add 288 g of citric acid to a 1L (1,000 ml) flask; add water 'til volume of solution equals 1 L. Note: Initially, add a smallish quantity of H2O in order to swirl-mix the citric acid & water; after powder is dissolved, top off the flask. Reaction 2: hydrochloric acid (+ Mg) FCPS Tchr's Resource Guide - Add 85.5 g HCl to 1L of H2O. Dr. Dave's recipe - [Note: Always add acid to water, not water to acid!] Note: 85.5 g HCl is approximately equivalent to 90 ml. Using 1L (1,000 ml) flask, add ~90 ml of HCl to ~910 ml of H2O. -- [Mon., 22 NOV '04] > Quest-Bowl - Q&A review game [Tue., 23 NOV '04] > Chem-Quest: Solutions thru endo-/exothermic reactions. After quiz, students answer activity questions on pp. 48-49. [Day before Thanksgiving Vacation] [Wed., 24 NOV '04] > Oscillating reaction demo. Make slime. > Alternate procedure: Make GAK (as per Margenau recipe, see below) or GAK-like substance (as per Dr. Dave's recipe involving Elmer's glue, borax solution, and corn starch); shrinking plastic activity (heating No. 6 recyclable polystyrene plastic in a toaster oven); demo separating H2O into H & O using Hoffman electrolysis apparatus [use universal indicator to show green neutral HOH, red acidic column (O gas, H + H liquid), and blue basic column (H gas, OH liquid)]; "Old Foamey" demo (catalyst + extreme exothermic reaction). Margenau's Recipe: [example of a chemical change & reaction] Background: GAK is a non-Newtonian fluid exhibiting properties of both a liquid and a solid (like Silly Putty). Materials: 20-Mule Team Borax (or sodium borate), Elmer's white glue (NOT school glue), water, food coloring (optional) and Zip-lock sandwich bags Directions: Combine 20ml of water and 20ml of glue in the zip-lock bag; mix well. (Add 1-2 drops of food coloring at this time.) Add 20 ml of borax to the glue-water mixture; knead well. The GAK will pull away from the bag easily. It may feel a little grainy, but that's O.K. -- it will become smooth with time. If some of the mixtures look watery, assure the students the water will be absorbed in time -- keep kneading, allow the bag to rest, and be patient! -- [After Thanksgiving] > Balancing Chemical Equations: Law of Conservation of Mass (& Energy); reactants; products; subscripts; coefficients. [29 NOV - 01 DEC] Optional: http://sciencespot.net/Pages/classchem.html#Anchor8 Student Worksheet - Snowman Challenge Worksheet & Answer Key (pdf) Snowman Cards - Front of Cards - Snowman Cards (pdf) and Back of Cards - Snowman Card Problems (pdf) ***Develop GenEd variation of Snowman Challenge: Students count atoms, complete DC&H accounting ledgers to show how equation is either balanced or unbalanced; circle unbalanced elements on ledgers.*** > Acids & Bases - "Colorful Chemical Clues" (C3) - Part 1: The Tests (pp. 51-56); Part 2: Presto Change-o (pp. 57-60). Note: Part 2 features "Analysis" questions re: writing & balancing chemical equations. - See msg. (under separate cover) re: provisioning for lab (groc. store list) - Use 2,000 mL flask to "brew" batch of "Purple Rain" (in honor of the artist formerly known as, "Prince"). 1/4 red cabbage per liter of water (use 1/2 cabbage for 2L). Simmer on hotplate (low) for several hours. Decant liquid; use plastic (or glass) stirring rod to extract cabbage leaves from flask. Refrigerate. - To avoid cross-contamination, use same containers from year-to-year: plastic vials for samples; droppers & dropper-holder vials. - After C3 - Part 1, recover ammonia and vinegar for use during Part 2 (Presto Change-o). [begin] BACKGROUND INFO ----------------------- - Acids, Bases, & pH Google Search: What is an ion? Ions are atoms or molecules that have lost or gained electrons. An atom or molecular fragment that has a positive electrical charge due to the loss of one or more electrons; the simplest ion is the hydrogen nucleus, a single proton. Google Search: "hydrogen ions" Anything that reacts with an acid is called a BASE. Any base that dissolves in water is called an ALKALI. Google Search: "hydroxide ions" "Acids, bases and salts contain ions of the element hydrogen. Ions are atoms or molecules that have lost or gained electrons. If atoms lose one or more electrons they become positively charged ions (cations). If they gain one or more electrons, they become negatively charged ions (anions). It is the presence of the hydrogen ions in solutions that allows us to measure the pH of a solution. The quantity of hydrogen or hydroxyl [hydroxide] ions in a solution determines whether the solution is acid or alkaline." - Google Search: what is pH? (chemistry) p(otential of) H(ydrogen); the logarithm of the reciprocal of hydrogen-ion concentration in gram atoms per liter; provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution (where 7 is neutral and less than 7 is acidic and greater than 7 is basic) The pH Scale The strength of an acid or an alkali can be measured by the concentration of hydrogen ions in it. The more hydrogen ions it contains, the more concentrated it is. For convenience, this concentration is turned into a number called the pH of the acid (standing for 'hydrogen potential'). As the pH of a liquid goes down, it becomes more acidic (less alkaline). As the pH of a liquid goes up, it becomes more alkaline (less acidic). The pH scale goes from 0 (strongly acidic) to 14 (strongly alkaline) with pure water (neutral - neither acidic nor alkaline) at 7 in the middle. Google Search: "litmus plant" litmus = plant pigment from red cabbage [incorrect?] litmus paper = strip of [filter] paper with dye on it [end] BACKGROUND INFO ----------------------- C3 - Part 2: Presto Change-o Provision approx. ~1 L (for three classes) of vinegar (v), cabbage juice (c), ammonia (a). "c" stands for both _c_abbage juice and _c_ontrol. DO NOT follow lab procedure directions -- use medicine cups to fill each test tube w. 10 ml cabbage juice rather than 15 ml (as directed). In practice, it's easier to mix liquids using slightly smaller initial volume. Demo Dr. V's technique for mixing liquids in a test tube. Seven (7) 250 ml beakers of three (3) liquids (v,c,a) shared among 14 stations: 42 test tubes; 14 test tube racks, 3 tubes per rack. Fill beakers to 100 ml (in case of spills); refill as necessary. Post-Lab Discussion: - Draw Bohr Model of hydrogen atom. Is the hydrogen atom in a stable configuration, that is, is it reactive or non-reactive? It's reactive. Remember, it takes two electrons to fill the first period (energy level), so hyrdogen has one electron to share with other atoms. If hydrogen loses an electron, it becomes positively charged (H+) -- talk about bass-ackwards! -- and is called an "ion." [Hydroxide ions (OH-) are negatively charged.] - What is an ion? - What is pH? Ratio of H+ to OH- ions. - Why is the pH of water (7) neutral? The H+/OH- ratio is 1:1! -- > "Where's the 'Juice'? Producing Electricity from Chemicals" - Do only Part 1: Lemon "Juice" [need 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: a : 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). ***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.] > Test Review: J-lab website + my activity (listing subset of questions related to GSLG). [Thu., 16 DEC '04] > Test Review: Test Bowl. Prizes: Hydrogen (H)ugs; Potassium (K)isses; Carbon (C)aramels. Grand Prizes: Monkeys plus assorted mini-bars. [Fri., 17 DEC '04] > GSLG Test [Mon., 20 DEC 2004] > Loose Ends: Bubble scan forms; collect GSLGs; distribute YSLGs ("For the next few weeks, we're going into heat!"); DEC Solstice & extra credit opportunity (EarthDial Activity); catalyst demo?. [Tue., 21 DEC 2004] > Makin' Flakes [Wed., 22 DEC 2004] == Winter Vacation == [Mon., 03 JAN 2005] (Re-entry mode) Video: "Cosmos" The Lives of Stars Q. If the Universe is mostly made of hydrogen and helium, then how do the other elements form? A. Inside stars! YSLG ---- [Tue., 04 JAN 2005] Begin Yellow Student Lab Guide (Investigating Matter and Temperature). Warm-up: Read p. 1, YSLG. Misc. notes & demos. Hot and Cold, Part 1: The Inside Story, pp. 3-5. [Wed., 05 JAN 2005] Hot and Cold, Part 2: Hot + Cold = ? (mixing vials of water). [Thu., 06 JAN 2005] Finish Part 2, Hot + Cold = ? POD, answer activity questions pp. 7-9. [Fri., 07 JAN 2005] [Note: Better sequence is to flip-flop Fri/Mon lessons.] POD. Tracking the Heat - Part 1: All Things Being Equal (CBL re: thermal equilibrium) [Mon., 10 JAN 2005] P.O.D. (dynamic equilibrium); explain formula for temp of a mixture; Worksheet, "Practice: Hot + Cold = ?"; EDD, p. 15, Tracking the Heat, Part 2: In Contact. [Tue., 11 JAN 2005] Tracking the Heat - Part 2: In Contact Repurpose EXP 11, "Radiant Energy" Lab Pro software settings: Double-click on graph; (Click tab, "Graph Options") Change Title to either "Tracking the Heat - Contact" or "Tracking the Heat - No Contact"; (Click tab, "Axes Options") Y-Axis Scaling 0(Bottom)-100(Top), X-Axis Scaling 0(Left)-20(Right). From the menubar, select "Experiment/Data Collection...": Length = 20 minutes; (check) Sample at Time Zero; 20 samples/minute or 0.05 minutes/sample. From the menubar, select "File/Save As..." *NOTE:* Six lab stations, four students per stn.: 3 "Contact"; 3 "No Contact." Print eight (8) copies of graph; share 4 copies with another group. ***Use 200 ml*** of hot & cold water; be sure cold water is VERY cold! [I tried a 4/2/2 set-up, with two computers per group -- *way too much goin' on!*] [Wed., 12 JAN 2005] Tracking the Heat, Part 2: In Contact. Review "perfect" graphs: reason initial temps not the same for both stations; slope vs. rate of heat transfer; thermal equilibrium; heat source/sink. Answer activity questions, pp. 18-21. [Thu., 13 JAN 2005] Bi-P.O.D.: (1) Slope of graph lines vs. rate of energy transfer; (2) did samples reach thermal equilibrium? Tracking the Heat, Part 2: In Contact. Review activity questions, #1-6 (?pp. 18-21?). [Fri., 14 JAN 2005] P.O.D.: T-sub-m. Handout: Temp. scales (NYSRE Earth Sci. Ref. Tables) & formulae. Intro. culminating activity, YSLG: "More Than Just Hot Air - Designing Your Own Experiment," pp. 51-52 (Honors class). Finish Tracking the Heat, Part 2: In Contact. Review activity questions, ?? (?pp. 18-21?). [Tue., 18 JAN 2005 (Two-hour delayed opening.)] * Bi-P.O.D.: Q. 15dF = ?C A. -9.52C Q. Titan's surface temperatures of 290 degrees below zero Fahrenheit = ?K A. -180.32C or +92.68K [Wed., 19 JAN 2005] * Intro three (3) methods of heat transfer Heat on the Move - Transferring Thermal Energy: Radiation; Conduction; Convection "Radiation Station," pp. 35-38. Use ESCP *metal* black & silver cans. Collect data 10 min. lamp on; 10 min. lamp off. Ward's Natural Science http://www.wardsci.com/product.asp_Q_pn_E_364172_A_Radiation+Lab+Activity Black METAL cans w. lids, set of 5 = $32.95 Silver METAL cans w. lids, set of 5 = $32.95 Clamp Lamp with Reflector = $12.95 [Fri., 21 JAN 2005] "Radiation Station" follow-on demo/lab activities: * Use CBL + light probe to measure/record reflectivity/absorption of assorted colors of construction paper (or paint chips). [Mon., 24 JAN 2005] Hand-out "Mr. Perfect" graph (radiation_20cm_analyzed-2x.xmbl). Review "Radiation Station" activity questions, pp. 37-38. [Tue.-Wed., 25-26 JAN 2005] * Infrared wxsat imagery (Honors and gen-ed) http://www.ssec.wisc.edu/~tomw/ams/amsimage.html For activity questions, see WoW! for 06 May 2002. http://www.wsanford.com/~wsanford/gr8ps/yellow/radiation_station/ ir_wxsat_image_activity.doc ir_wxsat_image_activity.html Provisioning: PC mobile lab; laptop/LCD; overhead projector (set-up on deskette in front of AV table, FoS). Review activity questions. Highlight the Gulf Stream ocean current (setting the stage for background reference in "Convection Station" lab activity). [See notes (under separate cover) re: activity revisions.] [Thu., 27 JAN 2005] "Conduction Station," pp. 23-26. Rods of Al, brass, plastic, and wood immersed in water; use timer to measure time for heat to move the length of the rods. - Vocabulary: Conductor; Insulator. - Key Concepts: Heat transfer by "direct contact." Works best in solids. Provisioning: Coffee urn, cups w. lids, rods, and timers. Note: Refreshing water after each trial requires LOTS of hot water! [Fri., 28 JAN 2005] > "Convection Station - Hot and Cold Bottles of Water," pp. 27-30. The preceding activity demos behavior of more & less dense fluids; the following demo illustrates a convection current (or cell) in a fluid. > Convection demo: boiling water and pasta. Day before lab activity: Warning to wear old clothes; demo magic trick. Provisions: Coffee urns (hot & cold); cooler & ice; 12-14 bottles; 6-7 catch basins; 12-14 600 ml beakers (300 ml H2O per bottle); food coloring; 6-7 laminated index cards; 6-7 hot gloves; colored pencils (for drawing observations). [Note to Chin: Bottles could/should be pre-drawn in lab manual.] Use very hot & cold water for high temp contrast. Before proceeding, students do "wet run" (not "dry run") with room temp water. (1) Cold on top; (2) Hot on top. [Wed., 02 FEB 2005] P.O.D.s: Video Daily Double! Demo convection current (or cell) using hot plate, 1000 ml beaker, and small pasta. Note: Flowing current invisible until adding "tracers" (pasta). Observe/sketch. [Thu., 03 FEB 2005] P.O.D.s: Video Daily Double! Review activity questions: "Conduction Station" [Note: Make connection between plastic = good insulator and fleece garments (100% polyester).]; "Convection Station." Pre-lab, "Turn Up the Heat! - Determining Boiling Point": Read background paragraph; draw "Prediction" graph. [Fri., 04 FEB 2005] "Turn Up the Heat! - Determining Boiling Point" (phase changes), pp. 39-45. Notes: Pre-heat hotplates to setting #8 (control = constant heat output); stir ice water mixture continuously [to avoid graph spikes ("hiccups")]. HONORS Pre-Lab: Determine heat output of hotplate in calories/minute. Calculate latent heat of fusion and latent heat of vaporization using mass of ice plus time to melt ice and boil water. Use electronic balances to zero scale for mass of empty beaker, then quckly determine mass of ice (H2O). H = mCdelta-T g/1 x cal/g-degC x degC Heat output burner (cal/min) = mCdeltaT/min LHF or LHV = cal/min x min/1 x 1/g LHF = 80 cal/g LHV = 540 cal/g [NYSRE Earth Science Reference Tables] > Equations * Latent Heat} solid to liquid (vice versa): Heat (cal) = mass x heat of fusion * Latent Heat} liquid to gas (vice versa): Heat (cal) = mass x heat of vaporization * Heat energy (lost or gained): Heat (cal) = mass x temp change x specific heat > Physical Constants * Specific Heat of Water (in cal/g Cd) = 1.0 Ice = 0.5 Water Vapor = 0.5 -- [Mon., 07 FEB 2005] Hand-out YSLG Study Guide. Post-lab discussion, phase change lab. Google Search: "latent heat of vaporization" http://www.physlink.com/Education/AskExperts/ae93.cfm "The difference in enthalpies comes from the fact that a liquid molecule is stabilized by interactions with other nearby molecules (therefore a small heat of fusion) and a gas has very little intermolecular stabilization (hence a large heat of vaporization). The confusion comes from *the idea that temperature is a measure of the average kinetic energy of a system, and since the temperature remains constant, the average kinetic energy must also remain constant.* *The extra energy required to cause a phase transition is actually potential energy. It is the energy required to overcome the bonds of nearest neighbors to the point that a phase transition can occur. So it really isn't a change in kinetic energy.*" Answered by: Joe Larsen, Ph.D. Chemistry, Rockwell Science Center, Los Angeles, CA [Tue., 08 FEB 2005] "Is Freezing Cold? - Determing Freezing Point" (phase changes), pp. 47-50. Precaution: Temp of water bath should be somewhere between 70-80C, otherwise test tube of Lauric acid will not cool to freezing point w/in 15 minutes (time period spec'd. by YSLG). Note: Why did temp STOP decreasing? Latent Heat of Fusion released during phase change from liquid to solid! [Wed., 09 FEB 2005] "Cold, Colder, Coldest" Note: Sony Mavica MVC-FD200 takes video (MPGs) up to 1.44 MB (memory size of floppy diskette). Better quality in 320x240 format; 5-, 10-, & 15-sec clips. BE SURE TO SHOOT MOVIES IN LANDSCAPE MODE!!! (No way to rotate MPGs.) - banana hammer - flask/balloon gas production/expanding balloon - "fog beaker" (CO2 sublimes in H20) - floating "party bubbles" on bed of CO2 in aquarium - "let it snow" (use liq. N to cool CO2-filled balloon; dry ice forms inside balloon) - shattering/crumbling flower(s) [Thu., 10 FEB 2005] > HONORS "More Than Just Hot Air - Designing Your Own Experiment," pp. 51-52. Honors only. Two options: (1) Increase efficiency of "An Insulated Cola Bottle." Use either hot or cold liquid. Collect "baseline" data; redesign insulating materials to increase efficiency (w/in guidelines spec'd. by Vernier activity). (2) Increase efficiency of "Heat Transfer by Conduction." Insulated cups filled with ~200 ml (~200 g) of either hot- or cold water. Heat (lost or gained) = m x C x Delta-T Specific Heat of Water = 1 cal/g-C % efficiency = heat gained/heat lost x 100 Provisioning: * Logger Pro > Physical Science with Computers > Exp 12 - An Insulated Cola Bottle [12a_Insulated_Bottle_4btl_v4.xmbl] * ESCP "Conduction" kits + 12b_Heat_Transfer_by_Conduction.xmbl Ward's Natural Science Heat Transfer Activity http://www.wardsci.com/product.asp_Q_pn_E_364177_A_Heat+Transfer+Activity Hubbard Scientific Heat Transfer Kit http://www.shnta.com/Product//3122-gp.htm Lessons Learned: - repurpose as "Insulation Station" follow-on activity - Revise activity sheet to include student predictions, and spaces to record data for analysis (statistics & linear fit). - #3 rubber stoppers (one-hole) fit perfectly in IBC soda bottles. - Predetermine volume of containers: IBC soda bottles: ~366 ml (almost full) "Conduction Kit" insulated cups (~450 ml max) [*Use 370 ml in each container. Use 1000 ml graduated cylinders to measure volumes. Mass of empty IBC bottle is 194.1 g.] - Order two- to three (2-3) "Heat Transfer Kits" (conduction). * MTJHA culminating activity: Create tissue paper (or lightweight plastic trash bag) hot air balloon activity. Need paint gun &/or VERY HOT blow dryer. > GEN-ED * Bill Nye video: "Heat" (Big Sweaty Guy, Vivian Cupcake, et al.); photocopy B.Hayward video guide [Fri., 11 FEB 2005] HONORS: MTJHA cont'd. GEN-ED: Review activity questions, phase change labs (melting/boiling & freezing). Evaporation: phase change from liq-to-gas; temp <100C. Boiling: phase change from liq-to-gas; temp = 100C. Good question for "Ask a Scientist": If air temp consistently = or > 100C, will water bodies (e.g., lakes) boil? Phase change worksheets (two versions) [Mon., 14 FEB 2005] <-- Valentine's Day HONORS: MTJHA cont'd. - Final Testing GEN-ED: Review activity questions, "Is Freezing Cold?" Quest Bowl, Part 1 (of 2?) [Tue., 15 FEB 2005] WPHS Guidance Counselors (scheduling rising 9th graders) [Wed., 16 FEB 2005] GEN-ED: YSLG Quest [Note: *Lots* of schedule disruptions/lost time due to WPHS Guidance visists, inclement weather, staff development in-service, etc. Net result: 2-3 weeks behind schedule!] [Fri., 04 MAR 2005] Per. 1-3: YSLG Unit Test ================================================================= Walter Sanford, Director Carl Sandburg Middle School Center for Sky Awareness 8428 Fort Hunt Road Sandburg Planetarium Alexandria, VA 22308 Fairfax County Public Schools Work: 703-799-6169 -6197 (fax) E-mail: wsanford@wsanford.com Home: 703-765-9392 AMS Project ATMOSPHERE Atmospheric Education Resource Agent & Water in the Earth System (WES) Resource Teacher SCSA, Geosystems, & Camp T-Equity - URL: http://www.wsanford.com/ =================================================================