Cloud&in&a&Bottle,&Plus&the&Pressure2Temperature&Law&
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Cloud&in&a&Bottle,&Plus&the&Pressure2Temperature&Law& Grade&Level:&Grade&628& Estimated&Time&for&Completing&Activity:!2!50%minute!periods! Parts!I!and!II!can!be!done!in!one!50%minute!period,!leaving!questions!I,!J!and!K!for!homework.!The! second!50%minute!period!can!be!used!to!discuss!predictions,!complete!Part!III,!and!discuss!results.!! Learning&Outcomes& & • • • • Students!will!demonstrate!relationship!between!pressure!and!temperature! Students!will!understand!evaporation!and!condensation.! Students!will!that!pressure!and!temperature!influence!evaporation!and!condensation! Students!will!identify!conditions!necessary!for!cloud!formation! Arizona&Standards&of&Learning& Grade&6& SC06%S1C2%02!through!05! SC06%S1C3%02,!05! SC06%S1C4%01,!02! SC06,!S6C1%04! SC06,!s6C2%01,!02!and!06! & Grade&7& SC07%S1C2%02!through!05! SC07%S1C3%02!through!05! SC08%S1C4%01,!02! ! ! Grade&8& SC08%S1C2%02!through!05! SC08%S1C3%02!through!05! SC08%S1C4%01,!02! ! Plus:!HS%S3C1%04! Materials& !A!clear!2L!bottle!with!the!label!removed! Cap!for!the!2L!bottle! Fizz!Saver!(available!at!most!large!grocery!stores,!or!online.!They!cost!about!$4.)! Thermometer!(alcohol!or!liquid!crystal)! Matches,!or!Paper!Towel!and!a!Lighter! Cool!Water! Warm!Water! Questions!Worksheet! ! Vocabulary& Cloud!condensation!nucleiAir!parcel! ! Background& Much!of!Earth’s!weather!can!be!understood!with!just!a!few!simple!concepts:! 1. Air!generally!cools!off!as!it!rises.! 2. Cold!air!doesn’t!hold!onto!water!well.! !Principle&1.&Air&cools&as&it&rises.!!It’s!colder!on!top!of!a!mountain.!Have!you!ever!thought!about!why?! That’s!because!air!pressure!is!lower!up!there.!! A!parcel!of!air!has!a!certain!amount!of!energy!in!it,!heat,!which!is!the!kinetic!energy!of!the!molecules! moving!around.!If!we!don’t!add!any!more!energy!to!it,!but!allow!the!air!parcel!to!rise!through!the! atmosphere,!the!parcel!will!start!to!cool.!That’s!because!the!surrounding!air!pressure!gets!lower!and! lower,!and!the!whole!parcel!will!expand.!That!means!each!little!molecule!is!responsible!for!occupying! more!space,!bouncing!around!over!larger!distances!to!keep!the!surrounding!atmosphere!at!bay.!That! takes!energy!!Because!the!parcel’s!energy!is!used!to!exert!pressure!on!the!surrounding!air,!there!is!less! energy!left!to!keep!the!parcel!warm.!Therefore,!as!the!air!mass!rises,!it!cools.! The!opposite!is!true!of!sinking!air,!which!tends!to!warm.!As!an!air!parcel!sinks!toward!Earth,!the! surrounding!pressure!increases,!the!air!parcel!contracts,!and!the!energy!that!was!previously!used!to! propel!those!air!molecules!over!a!big!space!isn’t!needed!anymore,!so!the!parcel!warms!up.!! The!relationship!between!pressure!and!temperature!is!summarized!by!Joseph!Louis!Gay%Lussac’s! Pressure%Temperature!Law:! ! ! where:! P1=initial!air!pressure!! T1 =initial temp P2=final!air!pressure!! T2 =initial temp ! Essentially,!what!this!equation!shows!us!is!that!pressure!and!temperature!are!directly!proportional—if!a! parcel!of!air!is!at!1!atmosphere!of!pressure!and!20C,!and!then!goes!to!2!atmospheres!of!pressure,!its! temperature!would!be!40C.!If!the!air!parcel!then!returned!to!1!atmosphere!of!pressure!again,!the! temperature!would!decrease!again!to!20C.!Hence,!when!air!rises!and!the!pressure!comes!off,!air!tends! to!cool.! Principle&2.&Cold&air&doesn’t&hold&water&well.!Water!is!more!soluble!in!warm!air,!and!will!tend!to! condense!into!droplets!when!the!air!cools.!This!is!why!we!have!clouds!more!than!fog:!water!evaporates! off!the!warm!Earth!into!air!parcels,!and!as!the!parcels!rise,!they!cool!off!and!the!water!condenses!into! clouds.! We!can!encourage!cloud!formation!by!giving!water!droplets!something!to!attach!to!(cloud!condensation! nuclei).!Most!any!particulate!or!aerosol!in!the!atmosphere!will!work—in!this!experiment,!we!use!smoke! from!a!match.! References:& CLOUDS:!Investigating!the!Climate!System!http://www.nasa.gov/pdf/62317main_ICS_Clouds.pdf! Animated!Charles!and!Gay%Lussac’s!Law:!http://www.grc.nasa.gov/WWW/k%12/airplane/aglussac.html! Why!is!the!air!cooler!at!higher!altitudes?! http://education.sdsc.edu/teachertech/downloads/climate_answ.pdf! A"Cloud"in"a"Bottle,"and"the"Pressure3Temperature"Law" Background:" Have%you%ever%touched%a%cloud?%What%did%it%feel%like?% Cold%and%wet,%probably:%clouds%are%made%of%little%water%vapor%(a%gas)%that%rides%up%into%the%atmosphere.% It’s%very%cold%up%there,%so%eventually,%that%water%vapor%gas%cools%to%make%liquid%water%droplets.%That% process%is%called%“condensation”.%The%water%vapor%is%invisible%to%our%eyes,%but%once%it%cools%to%make% droplets,%we%can%see%it:%that’s%what%we%call%“clouds”.%Some%clouds%are%so%cold%that%they%are%made%of%little% shards%of%ice!% Clouds%do%sometimes%touch%the%ground—we%call%that%“fog”—but%because%they%require%cool% temperatures,%they%usually%form%high%up%in%the%sky.%% Today%we%are%going%to%make%a%cloud%in%a%bottle%so%that%everyone%can%(almost)%touch%one.% Part"I:"Cloud"in"a"Cold"Bottle" 1. Pour%about%10%cm%of%water%into%the%bottle%and%replace%the%cap.%Make%sure%the%cap%is%tight.%% 2. Shake%the%bottle%for%a%few%seconds.% 3. Squeeze%the%bottle%firmly,%and%then%release%it.%Repeat%that%four%times.% % A. Describe*what*you*see*in*the*bottle*when*you*squeeze*and*release*it.* * 4. Have%the%teacher%place%a%lit%match%in%the%bottle%and%quickly%replace%the%lid.% 5. Wait%approximately%30%seconds%for%the%smoke%to%dissipate.% 6. Squeeze%the%bottle%as%you%did%in%step%3.% B.**Describe*what*you*see*in*the*bottle*when*you*squeeze*and*release*it,*now*that*there*is*smoke*inside.** C.*What*is*the*purpose*of*the*smoke?* D.*What*is*the*purpose*of*shaking*the*bottle?* E.*Why*do*you*think*the*cloud*comes*and*goes?*Make*an*educated*guess,*even**if*you*aren’t*sure.*You’ll* get*a*hint*in*Part*II.* Part"II:"Temperature"and"Pressure" 7. Place%a%thermometer%into%the%bottle.%Cap%the%bottle%with%the%Fizz%Saver.%% 8. Pump%up%the%fizz%saver%50%times%and%%record*the*temperature*in*the*table*on*your*data*sheet.% Repeat%for%100%pumps,%150%pumps,%etc.%all%the%way%up%to%200%pumps.% % F.*What*happens*to*the*pressure*inside*the*bottle*as*you*pump*the*fizz*saver?* * G.*What*happens*to*the*temperature*as*you*pump*the*fizz*saver?*If*you*observe*a*trend,*explain*why*you* think*the*trend*exists.* * H.*What*will*happen*to*the*temperature*when*you*loosen*the*cap?* * 9. After%recording%the%temperature%at%200%pumps,%loosen%the%cap%to%release%the%pressure%from%the% bottle.%Record%the%new%temperature%in%the%table%where%it%says%“Depressurized”.% I.*Plot*your*results*on*the*graph*on*your*data*sheet.*Use*GayMLussac’s*Law*to*fill*in*the*Pressure*column.* J.*Revise*your*prediction*from*Part*I.*Why*do*you*think*the*cloud*comes*and*goes?* " Part"III:"Cloud"in"a"Warm"Bottle"" K.*In*Part*III,*you*will*repeat*the*cloud*experiment*from*part*I*using*warm*water*instead*of*cold*water.*Do* you*think*the*cloud*will*be*better*(more*visible)*or*worse*(less*visible/no*cloud*at*all)?*Explain*why*you* made*that*prediction.* 10. Now%repeat%steps%1]6,%using%warm%water%in%place%of%cold%water.% % L.*Was*your*prediction*correct?* * Joseph*Louis*GayMLussac*(1778M1850)* One%smart%guy!%French%chemist%and%physicist%who%discovered% the%law%of%combining%gases,%among%other%pioneering%research.% % % % % % % Photographers%come%from%all%over% the%world%to%photograph%storms%in% the%Sonoran%desert,%because%the% clouds%are%so%high%here,%we%get%very%% long%lightning%streaks.%Why%is%that% so?%% Cloud&in&a&Bottle:&Questions&to&Answer& Part&I:& A.&&&&Describe&what&you&see&in&the&bottle&when&you&squeeze&and&release&it.& ! & & & & & & B.&Describe&what&you&see&in&the&bottle&when&you&squeeze&and&release&it,&now&that&there&is&smoke& inside.& & & & & & & C.&What&is&the&purpose&of&the&smoke?& & & & & & & D. What&is&the&purpose&of&shaking&the&bottle?& & & & & & & E. Why&do&you&think&the&cloud&comes&and&goes?&Make&an&educated&guess,&even&&if&you&aren’t&sure.& You’ll&get&a&hint&in&Part&II.& & & & & & & & & Part&II:&Temperature&and&Pressure& F. What&happens&to&the&pressure&inside&the&bottle&as&you&pump&the&fizz&saver?& & & & & G. What&happens&to&the&temperature&as&you&pump&the&fizz&saver?&If&you&observe&a&trend,&explain&why& you&think&the&trend&exists.& & & & & & & & & H. What&will&happen&to&the&temperature&when&you&loosen&the&cap?& & & & & I. Plot&your&results&on&the&data&sheet.& & & J.&Revise&your&explanation&from&Question&E.&Why&do&you&think&the&cloud&comes&and&goes?& & & & & & & & & & Part&III:&Cloud&in&a&Warm&Bottle& K.&In&Part&III,&you&will&repeat&the&cloud&experiment&from&part&I&using&warm&water&instead&of&cold&water.& Do&you&think&the&cloud&will&be&better&(more&visible)&or&worse&(less&visible/no&cloud&at&all)?&Explain&why& you&made&that&prediction.& & & & & & & & L.&Was&your&prediction&correct?& & & & & & & & Cloud&in&a&Bottle&Data&Sheet& & Pumps& Temperature& Pressure& 0& & 1&atm& 50& & & 100& & & 150& & & 200& & & $ $ where:$ & P1=$air$pressure$at$0$pumps$ & T1 =temperature at 0 pumps Depressurized& & & P2=$air$pressure$at$___$pumps$ & T2 = temperature at ___ pumps Fill$in$the$Pressure$column$using$ & the$Pressure1Temperature$$law:$ $ & & $ & P1,$T1$and$T2$you$will$determine$ experimentally.$P2$you$must$ calculate!$ & & & & Graph&of&Air&Temperature&vs.&Number&of&Pumps&(Pressure)& Te mp era tur e& & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & No.&of&Pumps& & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & & &
