material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Solubility, Solute,
Solvent
Solubilit y of Packing Peanut s:
Lab Act ivit y
Developed by: Mary Agnes Baum, Teacher
( maryagnes_ baum@hermit age.k1 2 .pa.us)
T able of Cont e nt s
Overview...........................................................................................
Science St andards Addressed ..........................................................
Goals/ Object ives .............................................................................
Mat erials and Equipment ..................................................................
Key Vocabulary Words .....................................................................
Saf et y ...............................................................................................
Procedure ( t ot al est imat ed t ime- 1 hr) ............................................
Assessment Examples ......................................................................
Locat ing Mat erials ............................................................................
Background Inf ormat ion ...................................................................
Ref erences........................................................................................
Acknowledgement ............................................................................
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Ove rvie w
This lesson explores t he concept of a solut e and solvent . St arch and
St yrof oam packing peanut s are dissolved in wat er and acet one t o
demonst rat e polar and non-polar solut es and solvent s. St udent s f irst
est imat e, t hen measure, t he number of packing peanut s t hat will dissolve
in 5 0 mL of solvent .
Scie nce St andards Addre sse d
U.2 Evidence, models, and explanat ions
A.1 Abilit ies necessary t o do scient if ic inquiry
B.1 Propert ies and changes of propert ies in mat t er
E.2 Underst andings about science and t echnology
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material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Solubility, Solute,
Solvent
Goals/ Obje ct ive s
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•
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St udent s will classif y polymers as nat ural or synt het ic.
St udent s will def ine and ident if y t he solvent and solut e in a
solut ion.
St udent s will dist inguish bet ween a polar and a non-polar molecule.
Mat e rials and Equipme nt
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St arch packing peanut s
St yrof oam ( polyst yrene) packing peanut s
Acet one
1 0 0 mL beakers
St irring rods
Saf et y goggles
Ke y V ocabulary Words
Poly me r - A class of nat ural or man made subst ances made f rom smaller
unit s called monomers arranged in long chains.
Solubilit y - Amount or abilit y of one mat erial t o dissolve in anot her.
Polar Mole cule - A t ype of molecule t hat will dissolve in wat er.
Non- polar Mole cule - A t ype of molecule t hat will dissolve in non-polar
subst ances.
Solut e - The subst ance t hat get dissolved.
Solve nt - A subst ance t hat dissolves anot her Subst ance. Solvent s are
of t en liquids.
Saf e t y
Safety goggles are required for this activity. Students should
be careful not to get acetone on their hands or directly inhale
acetone vapor. Be aware that acetone is flammable and will
dissolve ink.
Proce dure ( t ot al e st imat e d t ime - 1 hr)
Set -Up ( 5 minut es)
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material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Solubility, Solute,
Solvent
Make sure each lab group has t wo 1 0 0 mL beakers and t wo st irring rods.
Have a large supply of St yrof oam and St arch packing peanut s ready.
During ( 4 5 minut es)
Part 1 :
Obt ain t wo packing peanut s labeled “ A” ( st arch) and t wo labeled “ B”
( polyst yrene) f rom t he inst ruct or. Writ e down at least t hree dif f erent
propert ies f or each t ype of packing peanut . Fill a 1 0 0 mL beaker wit h 5 0
mL of wat er and a second 1 0 0 mL beaker wit h 2 0 mL of acet one.
Prepare a dat a t able, labeling one column peanut t ype, one column wat er
and one column acet one. Beneat h t he peanut t ype column, writ e “ A” and
“ B” on separat e rows. Under t he wat er column, writ e “ dissolves” or
“ does not dissolve.” Repeat f or t he acet one column. Add one packing
peanut labeled “ A” t o t he beaker of wat er. Record in t he dat a t able
eit her dissolves or does not dissolve. Next , add t he second packing
peanut labeled “ A” int o t he beaker of acet one. Record observat ion as
dissolves or does not dissolve. Repeat procedure wit h packing peanut s
labeled “ B.” Answer quest ions under Part 1 .
Part 2 :
Est imat e how many “ A” packing peanut s will dissolve in 5 0 ml of wat er
and how many “ B” packing peanut s will dissolve in 2 0 mL of acet one.
Then add t he “ A” packing peanut s one at a t ime t o t he wat er t o
det ermine t he act ual number t hat will dissolve. Record t he act ual value.
Repeat t he procedure wit h t he “ B” packing peanut s and t he acet one.
Record t he act ual value. Answer t he Part 2 quest ions:
Tear-Down ( 5 Minut es)
Gat her all used lab equipment . Used polyst yrene can be recycled.
Asse ssme nt Example s
Part 1 :
1 . Why did packing peanut “ A” dissolve in wat er but not in t he
acet one?
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material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Solubility, Solute,
Solvent
( Packing Peanut “ A” is a polar mat erial and will not dissolve in
acet one a non-polar solvent . “ A” will however dissolve in wat er, a
polar solvent .)
2 . Why did packing peanut “ B” dissolve in t he acet one but not in t he
wat er?
( Packing Peanut “ B” is a non-polar mat erial and will not dissolve in
wat er a polar solvent . “ B” will however dissolve in acet one, a nonpolar solvent .)
3 . What is a solvent ?
( A solvent is t he t hing, of t en a liquid, which dissolves somet hing
else.)
4 . What is a solut e?
( A solut e is t he t hing, somet imes a solid, which get s dissolved) .
5 . Ident if y t he solvent s and solut es f or each set of condit ions.
( The packing peanut s are solut es, acet one and wat er are t he
solvent s.)
6 . What is t he dif f erence bet ween a polar and a non-polar molecule?
( A polar subst ance will dissolve in polar solvent s, like wat er. A nonpolar subst ance will dissolve in non-polar solvent s like acet one, or
gasoline) .
7 . Which packing peanut is a nat ural polymer and which is a synt het ic
polymer?
( Packing Peanut “ A” is t he nat ural polymer st arch. Packing Peanut
“ B” is t he synt het ic polymer polyst yrene.)
Part 2 :
1 . How did t he act ual number of packing peanut s compare t o your
est imat ed value?
( Answers will vary, but many st udent s will underest imat e t he
number packing peanut s which will dissolve in 2 0 mL of acet one.)
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material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Solubility, Solute,
Solvent
2 . Were you surprised by t he act ual number of packing peanut s t hat
dissolved? Explain.
( Some st udent s will be surprised, ot hers will not . Most of t he
volume in a packing peanut is t aken up by air. This makes it seem
like t here is more mat erial in each packing peanut , and t heref ore it
looks like f ew will dissolve. The solubilit y of bot h t he solut es in
t heir respect ive solut e is also high.)
3 . Why it would not be a good idea t o t ransport gasoline in a
polyst yrene cont ainer?
( Gasoline, being a non-polar solvent , would likely dissolve t he
polyst yrene cont ainer.)
Locat ing Mat e rials
Packing peanut s can be f ound in shipping boxes and at shipping out let s.
Acet one can be f ound at t he hardware st ore in t he paint sect ion.
Background Inf ormat ion
St yrof oam packing peanut s are made f rom blow molded polyst yrene. The
name St yrof oam is pat ent ed by t he Dow Chemical Corporat ion and was
discovered in 1 9 4 1 by Ray McInt ire. Polyst yrene is ident if ied in ot her
product s by resin ident if icat ion code ( recycle code) six. It is used in CD
cases, some f ood cont ainers and disposable pet ri dishes. Alt hough blow
molded polyst yrene is less dense t han wat er, solid polyst yrene has a
densit y of about 1 .0 5 g/ cm 3 and will sink in wat er.
The st arch packing peanut s are a nat ural mat erial usually made f rom corn
st arch. The use of st arch based packing peanut s st art ed in t he 1 9 9 0 ’s.
St arch packing peanut s are biodegradable and non-t oxic. They are saf e
when accident ally consumed by people or pet s, but t hey are not t ast y.
St arch packing peanut s will dissolve f ast er in hot wat er t han cold wat er.
The st arch molecules are polar and cont ain hydroxyl ( -OH) groups. These
–OH groups hydrogen bond wit h wat er molecules and as a result t he
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material science teachers’ aide
Unit: Properties of Matter
Subject: Physical Properties
Grade Level: 7– 9
Key topics: Solubility, Solute,
Solvent
st arch dissolves in wat er. Polyst yrene has no hydroxyl groups and is nonpolar. Theref ore polyst yrene will not dissolve in wat er.
Re f e re nce s
Polymer Ambassadors ht t p:/ / www.polymerambassadors.org
American Ext rusion Int ernat ional ht t p:/ / www.americanext rusion.com
Perry A. Cook, Sue Hall, and Jill Donahue “ Pondering Packing Peanut
Polymers” Journal of Chemical Educat ion Vol 8 0 No 1 1 2 0 0 3 p1 2 8 8 B
Acknowle dge me nt
This module was developed by t he ASM Foundat ion K-1 2 commit t ee' s
Middle School Task Force wit h input f rom t eachers and st af f and edit ing
assist ance f rom Pet er Kazarinof f , all of whose cont ribut ions are
acknowledged wit h t hanks.
Copyright ASM International 2010; Permission is granted for
free use by instructors for educational purposes.
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