Effects of Acid Rain on Leaves By Harry & Mitchell
Effects'of'Acid'Rain'on'Leaves!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Harry!&!Mitchell! ! Objective'Question' !
What!is!the!effect!of!acid!rain!on!different!types!of!leaves?!! !
Variables' ! Independent' ! •! Type!of!leaf! !
•! Acid!rain!solution!pH!level! •! Acid!rain!solution!concentration!
Dependent' ! •! Changes!in!leaf!cell!structure!
•! Type!&!size!of!slides!and!cover!slides!
Controlled' !
•! Size!of!graduated!cylinder!
!
•! Type!&!size!of!microscope! •! Leaf!sample!size!
•! Size!of!beakers!
•! Volume!of!distilled!water! •! Volume!of!sulfuric!acid! •! Volume!of!acid!rain!solution!
•! pH!testing!probe!type!and!size!
' Materials'List' !
•! 500!mL!0.001!molar!sulfuric!acid!
•! 1!Razor!or!scalpel!
•! 1!microscope!set!(microscope,!slides,! cover!slides,!etc.)!
•! 500!mL!distilled!water!
•! 1!pair!of!latex!gloves!(or!hand!covers! of!some!sort)!
!
•! 3!different!leaf!samples!
•! 2!100!mL!beaker!!
•! 1!pH!testing!kit!(probe)!
•! 1!50!mL!beaker!
•! 1!tweezer!
•! 2!100!mL!graduated!cylinder!!
•! 1!stirrer!
Procedure' ''
•! 1!dropper!
Leaf'Sample'1'
!! Making'the'acid'rain'solution' !
1.
Measure!70!mL!of!distilled!water!using!the!graduated!cylinder!
2.
Pour!the!distilled!water!into!a!100!mL!beaker!
3.
Using!the!pH!probe,!test!the!pH!of!the!water!
4.
Measure!30!mL!of!sulfuric!acid!using!the!graduated!cylinder!
5.
Pour!the!sulfuric!acid!into!a!100!mL!beaker.!!
6.
Use!the!dropper!to!squeeze!drops!of!sulfuric!acid!into!the!distilled!water!
7.
Continue!squeezing!sulfuric!acid!into!the!distilled!water!until!the!pH!measures!3!
8.
Pour!30!mL!of!the!acid!rain!solution!into!a!graduated!cylinder!
9.
Pour!the!acid!rain!solution!into!the!50!mL!beaker!
10. Stir!gently!with!the!stirrer! !! Analyzing'the'leaf'sample' !
1.
Using!the!scalpel,!cut!a!small!square!1cm!x!1cm!from!the!leaf!close!to!the!middle!vein!
2.
Place!the!leaf!on!a!microscope!slide!
3.
Put!a!drop!of!water!onto!the!leaf!and!cover!it!with!the!cover!slide!
4.
Observe!and!make!qualitative!observations!about!the!leaf!under!the!microscope!
5.
Place!the!leaf!in!the!solution!using!the!tweezers!
6.
Set!a!timer!for!15!minutes!
7.
Wait!for!the!timer!to!end!and!retrieve!the!leaf!!
8.
Clean!the!leaf!and!place!it!under!the!microscope!again!following!steps!2X4!
9. !!
Observe!the!differences!before!and!after!
! ! ! !
Leaf'Sample'2'
!! Use!the!same!acid!rain!solution! !! Analyzing'the'leaf'sample' !
1. ''
Follow!steps!1X9!in!the!procedure!for!Leaf!Sample!1!regarding!“Analyzing!the!leaf!sample”!
Leaf'Sample'3'
!! Use!the!same!acid!rain!solution!! !! Analyzing'the'leaf'sample' !
!
1.! Follow!steps!1X9!in!the!procedure!for!Leaf!Sample!1!regarding!“Analyzing!the!leaf! sample!
Observations'Table' !
Observations!Table! Qualitative! Observations! Trial!1!Initial! Observations!
Trial!1!Final! Observations!
Large!Leaf! Green!cell!walls!can! be!clearly!seen! Cell!walls!dark!green! Light!green!innards! Cell!walls!are!all! different!shapes! (generally!same!size)! mostly! Closely!packed! together,!no!extra! space!in!between! ! Cell!walls!are! breaking!apart! Cell!walls!not! connected! Don’t!fit!as!well! Seems!broken!apart! Cells!are!thicker! !
Leaf!Type! Small!Leaf! Green!cell!walls!can! be!clearly!seen! Cell!walls!dark!green! Light!green!innards! Cell!walls!different! shapes;!sizes!vary!a! lot!(some!five!times! bigger!than!others)! Closely!packed! together! !
Mint!Leaf! Dark!green!–!major! leaf!area! White!vein! Cells!are!not!obvious! Seems!like!there!are! shapes!–!may! represent!cells! Some!cells!lighter!than! others! !
Hole!in!one!of!the! cells! Not!as!prominent!as! before! Some!walls!are!still! there,!others!were! dark!blobs! Dark!splotches!in!the! middle!of!the!cells!
White!vein!in!the! middle!is!turning!a! pale!green! Dark!part!of!the!leaf!is! considerably!darker! Less!white!cells!or! whiter!cells!in!the! main!body! There!are!streaks!of!
Trial!2!Initial! Observations!
Trial!2!Final! Observations!
Cell!walls!are! dark!green!beside!the! noticeably!thicker!and! white!vein! there!are!gaps! ! between!some!of! them! Some!cells!are! completely!green!or! completely!dark! ! Main!body!dark! Main!body!dark!green! Cells!in!vein! green! Cell!walls!even!darker! Main!body!is!dark! Some!cells!lighter! green! green!with!white! color! Cell!innards!lighter! scattered! Cell!wall!–!basic! green! Main!vein!branches! outline!of!cell! Some!cells!are!lighter! off! Few!light!cells! than!other! Color!of!vein!is!white! ! ! ! ! Lots!of!more!clear! A!lot!of!lighter!green! Light!green!areas! thicker!boarders! cells! Main!body!is!very!dark! More!dark!green!cells! Less!dark!green! green! White!cells!scattered! Some!cells!clumped! Veins!not!as!white,! Large!splotches!of! together! slightly!green! dark!green! Some!cells!less! Cells!are!less!defined! Some!cells!more! defined! Some!areas!that!are! defined!than!other! Dark!green!splotches! really!light!green! Some!cells!are! between!light!green! Close!to!vein!are!dark! clumped!together! cells! green!splotches! ! Come!cells!are!more! ! light!than!the!already! ! light!cells! !
!
!
Evaluation' !
Our!experiments!were!quite!successful,!but!there!was!one!major!problem.!The!big!problem! regarding!our!experiment!was!the!time.!In!order!to!fully!show!the!effects!of!acid!rain!on!the! leaves,!we!need!a!longer!time!span!so!the!leaves!have!prolonged!exposure!the!!solution.!In!our! case,!due!to!time!restraints,!we!could!only!spend!15!minutes!for!each!leaf!sample.!The!result!is! that!the!effects!towards!the!leaf!and!cell!structures!are!minimal.!Also,!the!pH!regarding!the! sulfuric!acid!could!have!been!recalculated.!When!we!attempted!to!create!the!acid!rain!solution,! we!had!to!use!more!acid!compared!to!the!amount!of!water!used.!With!a!more!higher!molarity! sulfuric!acid,!we!could!have!decreased!the!amount!of!sulfuric!acid!used!but!also!made!the!pH!
results!of!the!solution!more!accurate.!As!well!as!that,!the!microscope!observations!was!also!a! little!problematic.!In!certain!observations!clear!pictures!of!the!cellular!structure!of!the!leaf! sample!could!be!seen.!However,!other!times,!the!observation!wasn't!as!clear,!and!we!couldn't! control!the!spot!that!we!were!observing.!That!proved!to!be!a!problem!because!we!had!a!hard! time!locating!what!part!was!the!cell!walls.!Finally,!a!problem!in!the!procedure!was!that!we! should!have!included!multiple!trials.!In!the!start!there!was!only!one!trial!included!for!all!the!leaf! samples.!In!the!end,!we!had!to!do!two!in!order!to!guarantee!our!results!were!not!outliers.!!
' Conclusion' !
This!experiment!showed!us!that!the!leaves!suffered!problems!regarding!cellular!structure!after! exposure!to!the!acid!rain!solution.!There!were!clumps!of!cells!after!exposure!to!the!acid!rain! solution,!and!many!cells!had!problems!with!the!cell!walls.!In!one!case,!with!our!first!leaf!sample,! some!of!the!cell!walls!actually!seemed!to!break!apart!and!the!cells!clumped!together.!In!other! cases,!when!the!cell!walls!were!harder!to!see,!tit!was!obvious!that!there!were!color!changes!on! the!leaf.!In!all!the!leaf!samples,!the!leaf!seemed!to!become!a!darker!shade!of!green!after! exposure!to!acid!rain.!Many!leaves!had!cells!that!had!centers!that!were!light!green.!However,! after!exposure!to!the!acid!rain!solution,!many!cells!had!turn!a!darker!shade!of!green,!and!the! also!clumped!together,!probably!indicating!again!the!cellular!problems!when!exposed!to!acid! rain.!Therefore,!this!supports!the!fact!that!the!leaves’!cellular!structure!would!be!harmed!due! to!exposure!to!acid!rain.! ! !