Egg#Osmosis#Lab#
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Introdu ctio n:##
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Cells!have!an!outer!covering!called!the!cell!membrane.!This!membrane!is!selectively!permeable;!it!has !tin y !p o r es !o r!
holes!that!allow!objects!to!move!across!it.!The!cell!membrane!controls!what!moves!in!and!out!of!the!cell.!Food!and!
oxygen!move!into!cells!across!the!cell!membrane!through!the!process!of!diffusion.!Diffusio n !is !movem ent!of!a!
substance!from!an!area!of!high!concen tration!to!an!area!of!low!con centration .!Osmosis#is!a!special!ty p e !of!
diffusion;!it!is!the!diffusion!of!water!across!a!se lec tiv ely !p er m e ab le !m e m b r an e .!Os m o sis !oc cu rs!when!wa te r!m o v es !
from!an !are a !w h e re !it!is!m o re !co nc e ntr at ed !to !an !ar ea !w h e re !it!is!les s!co n ce n tra te d.!!
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In!this!lab!you!w ill!be!usin g!an !eg g!w ith!th e!she ll!rem o ved .!Th e!she ll-less!egg!will!rep resen t!a!cell!and!its!selectively!
permeable!membrane.!You!will!remove!the!shell!of!the!egg!by!soaking!the!egg!in!vinegar.!The!egg!shell!is!made!up!
of!the!mineral!calcium!carbonate.!Calcium!carbonate!dissolves!in!acids!such!as!vinegar.!During!this!process!it!
releases!the!gas!carbon!dioxide.!After!the!shell!has!been !dissolved,!only!the!m em b rane !will!remain !around !the!egg.!!
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Safety#notes:##
1.!Raw!eggs!can!carry!salmonella!(harmful!bacteria).!Be!sure!to!wash!your!hands!after!handling!the!eggs.!!
2.!Handle!your!egg!very!carefully!so!that!it!does!not!break!!
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Pre#lab#Questions:##
1.!What!do!you!think!would!happen!to!a!shell-less!egg!if!w a ter !pa sse d !into !th e!eg g !thr ou g h !the !m e m b ra n e? !!
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2.!What!do!you!think!would!happen!to!a!shell-less!egg!if!w a ter !pa sse d !ou t!o f!the !eg g!through!the!membrane?!!
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3.!What!substance!must!pass!through!the!shell!and!membrane!in!order!for!a!chick!to!develop!correctly?!!
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4.!What!would!happen!to!the!developing!chick!if!the!egg!membrane!did!not!work!correctly?!!
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Purpose:##
To!soak!an!egg!in!various!liquids!and!obs erv e!h o w !th e!siz e!o f!the !eg g!c h an g es!a s!it!ga in s!or !lose s!w a te r!th ro ug h !th e!
membrane.!!
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Materials:##
Raw!eggs,!300!m l!v inegar,!tap!water,!s a lt !water,!an d !a !l iq u i d !o f!y our!choic e ,!metric!tape,!balan c e ,!plastic!co n t a in e r !
to!hold!egg,!beake r,!marker,!masking!tape!!
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Hypothesis:##
Predict!how!eggs!will!respond!when!it!is!soaked!in:!!
1.#Vinegar:#
2.#Distilled#Water#
3.#Corn#Syrup
4.#Salt#Water
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!"#$%&'"%()*%+(,-()#./012(%22(01(301%2."((
1.#Label#your#container#with#your#section#and#table#number.#
2.#In#the#data#table,#m ak e#a#dra w ing#an d #obs erva tion #of#the#e ggs #in#the#app ro pr iat e#s p a ce #
3.#To#Measure#Your#Eggs,#use #a #fle x ib le #t a p e #measure ,#measure#t h e #ci rc u mference #o f #th e #e g g #(a long#the#“e q uator”).#
Record#circumference#to#closest#millimeter#
4.#Weigh#the#eggs#in#gram s.#R e co r d#mass#
5.#Pour#300#ml#of#vinegar#into#the#container.#
6.#Carefully#place#eggs#into#the#c on t ain e r#a n d #allo w#it#to#soak#2 #da y s.#L o os e ly#p la ce #lid #o n #to p ;#if#p la ce d #to o #tig h t#it#may#
break!#
7.#Put#your#container#in#the#designated#space.#
8.#Clean#up#materials#and#wash#your#hands.##
!Vinegar#
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!"#$%&'"%()*%+(4-()#./012(%22(01(&05*066%&(7.*%"8($#"1(59"'+ 8(5. 6*(7.*%"((
1.#Carefully#remove#eggs#from#the#co nta ine r#of#vine ga r.#
2.#Remove#any#remaining#bits#of#shell#by#gently#running#eggs#under#water.#Blot#it#dry#with#a#paper#tow e l##
3.#Measure#and#mass#your#eggs#and#record#observations#in#data#table#
4.#Pour#used#vinegar#down#the#drain.#Rinse#conta iner#
5.#Place#3#eggs#in#separate#liquids:#distilled#water,#corn#syrup,#salt#water#
6.#Allow#each#egg#to#soak#2#days#
7.#Put#containers#in#de sig n a te d #sp a ce ,#cle a n #up #materials#and#wash#your#hands.#
!!!!! !!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!
! !!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!! !
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####Distilled#Water# # # #Corn#Syrup# ###############################Salt#Water#
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Liquid#
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Mass#(g)#
Final#Mass#
(g)#after#
soaking#
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%#Weight#Change#
Initial/Final#x#100#
Distilled#
Water#
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Salt#Water#
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Corn#Syrup#
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R1.69505(S'%5*0#15((
1. What#liquids#caused#the#egg#to#swell?#Cite#evidence#from#your#data#table.#
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2.#What#liquids#caused#the#egg#to#shrink?#Cite#evidence#from#your#data#table.#
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3.#What#process#caused#the#egg#to#swell#or#shrink?#Illustrate#this#proc ess#b elo w .#
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