Kelly ReuPresentation

8/13/2019 Kelly ReuPresentation

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Science and PropertyScience and Propertyof Sugar Glassof Sugar Glass

By: Sean KellyBy: Sean Kelly

Advised by Dr. Bill HeffnerAdvised by Dr. Bill Heffner

July 29July 29thth, 2006, 2006


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OverviewOverviewProject Overview:

o The goal of my project was to investigate sugar glasses and their

properties and relate them to traditional glass properties in a wayfor high school students to understand and appreciate.

o The goal was also to perform experiments for students involving

sugar glasses to demonstrate these properties.

I developed experiments involving:

Density Refractive Index Composition Fiber Drawing


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BackgroundBackground Glass has an amorphousstructure, which means

there is no crystallinestructure.

The crystalline solid

shown in the left of thepicture demonstrates arigid atomic structure.

The glass solid on theright demonstrates a non-crystalline atomic

structure.


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Forming GlassForming Glass

Glasses are formed by cooling the

liquid sufficiently fast so that the atomsdo not get a chance to form into thecrystalline pattern that they would liketo.

Candy glasses are formed the sameway. The melt is cooled to atemperature below the glass transitiontemperature ( Tg ).

If the melt is cooled too slowly, thencrystals will form and it will not forminto a glass.

Crystal Structure


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Candy and GlassCandy and Glass Traditional glasses are mainly madeup of silicon dioxide (sand) withother elements in lesser quantities tolower glass temperature of glassformation and improve otherproperties, such as CaCN3 (lime) andNaCO3 (washing soda).

The sugar glass I made was acombination of household sugar(sucrose), corn syrup(glucose/fructose mixture), and

water.

The water and corn syrup are addedas modifiers to help lower themelting point of the solution and

suppress crystallization.

Sugar Crystals


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Pouring TemperaturePouring Temperature

The temperature at which a given sugar solution can be cooled to

form a glass at a room temperature varies on the percent compositionof each material.

Before we could investigate a range of glasses with differentcompositions, a standard for pouring had to be established.

Fortunately, a methodology already existed. Confectioners for yearshave gone by a system of rating the candy on its hardness by dropping aspoonful into room temperature water. The candy can vary from softball to hard ball to hard crack. It is simply based on what the candy feels

like to touch. When the candy snaps or cracks when dropped intowater, it is at hard crack, and that is the point where it will become aglass if cooled at room temperature. That is the considered the pouringtemperature.


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ExperimentingExperimenting To find the optimal glassforming composition, a series ofsamples were made with varyingamounts of sucrose and cornsyrup.

Each day observations weretaken about the crystallization ofthe samples.

It was eventually concludedthat as the percent corn syrup inthe sample increased, the affectof crystallization decreased.

The composition of thissample is 50% sucrose,

40% syrup and 10% water

Day One

Day Two

Day FiveThe composition of thissample is 30% sucrose,

60% syrup and 10% water


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Pictures taken after one day.

Stable Glass Forming Region(Minimal Crystallization)

Subsequent

Crystallization

(Severe

Crystallization)

Syrup

Sugar Solution Ternary DiagramWater

CornSyrup

Sugar

Despite the amountof water in the

solution, it will not

form a glass until most

of it has boiled off,therefore the only area

of concern is the

percent sucrose versus

percent corn syrup.


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Specific Gravity ExperimentSpecific Gravity Experiment A specific gravityexperiment was set up inhopes of finding a

correlation involving thecomposition.

Specific Gravity, p = (wt of glass) / (wt of glass) (wt of jar) ,

where wt of jar is the difference between the weight of water in the jar andthe weight of the water and glass in the jar.

Step 1: Measure weight of jarand water.

Step 2: Measure weight of glass.

Step 3: Measure weight of jarand glass together.

It was first performed using pieces of glass (with a known specific gravity)

and once successful, was adapted for testing sugar glass.


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Specific Gravity Results (Glass)Specific Gravity Results (Glass)

Many surprisinghurdles had to beovercome, such as thedifficulty of eliminating

all air bubbles, buteventually solid data

was ascertained.

Specific Gravity vs. Trial #

1.64

1.65

1.66

1.67

1.68

1.69

1.7

0 1 2 3 4 5 6

Trial #

SpecificGravity

This led to an average specific gravity of 1.674


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Specific Gravity Results (Candy)Specific Gravity Results (Candy) To measure the specific gravity of the candyglass, the candy was poured into a mold (filmcontainer) that was ideal for the size of the jar.

The process was then repeated for the candysamples similar to that of the pieces of glass.

Specific Gravity vs. Composition

1.45

1.47

1.49

1.51

1.53

1.55

0 20 40 60 80

% Karo (with water = 10%)

S

p.G

ravity

Density

best fit

The data and theresulting graphshow a small trend

of increasingspecific gravitywith increasingcorn syrup.


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Fiber Drawing DemoFiber Drawing Demo Since one of the aims of my

project is to help convey theinteresting properties of glass to

high school students, a hands onexperiment was created for thesestudents to experience glass fiberdrawing using candy glass.

In the demo they were able to

experience the properties and theuses of drawing fiber. They alsoexperienced some of the scientific

issues involved in pulling glass

fibers.

The stable glass range on theternary diagram helped to select

an ideal composition for bothstability and good glass pulling

for the demo.


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Index of Refraction (Future)Index of Refraction (Future) Although the experiment has not beencompleted yet, I am hoping to finish it by the endof the program.

Index of refraction can be measured easily byusing a simple student spectrometer that mosthigh schools would have. It is important that the

only instruments being used are those that wouldbe available to high school students.

The spectrometer works by directing lightthrough a glass prism with known angles and

finding the minimum angle of deviation. Theindex can then be found using the equation

below.

Index of Refraction =Sin( (A + )/2) / Sin ( A/2),

where A is the angle of the prism and is the

minimum angle of deviation.


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Index of Refraction (Future)Index of Refraction (Future) To make a candy glass prism, atechnique had to be developed for a

mold where the candy could easily be

removed with ruining the sample.

Currently, candy is being poured intometal prism molds that have beenmade to be 90-45-45 degree triangles

in order to act like a glass prism.


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Further ReadingsFurther Readings J.E. Shelby,J.E. Shelby, Introduction to Glass Science and Technology,Introduction to Glass Science and Technology, 22ndnd Ed.Ed.

(Royal Society of Chemistry, Cambridge, UK, 2005)(Royal Society of Chemistry, Cambridge, UK, 2005) Arthur Hardy and Fred Perrin,Arthur Hardy and Fred Perrin, The Principals of OpticsThe Principals of Optics, 1, 1stst Ed.Ed.

(McGraw(McGraw--Hill, New York, 1932)Hill, New York, 1932)

Mary Anne White,Mary Anne White, Properties of MaterialsProperties of Materials. (Oxford University. (Oxford University

Press, Oxford, 1999)Press, Oxford, 1999)

HeinzHeinz PfaenderPfaender,, Schott Guide to Glass,Schott Guide to Glass, 22ndnd Ed. (Chapman & Hall,Ed. (Chapman & Hall,

New York, 1996)New York, 1996)

RobertRobert DoremusDoremus,, Glass ScienceGlass Science. (John Wiley & Sons, New York,. (John Wiley & Sons, New York,1973)1973)


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Sources CitedSources Cited http://www.ohsu.edu/research/sbh/resultsimages/crystalvsglass.gihttp://www.ohsu.edu/research/sbh/resultsimages/crystalvsglass.giff

https://reader010.{domain}/reader010/html5/0621/5b2b5ad1e0190/5b2b5ae063a4d.jphttps://reader010.{domain}/reader010/html5/0621/5b2b5ad1e0190/5b2b5ae063a4d.jp http://www.industryplayer.com/images/licrespic/sugar%20crystals.http://www.industryplayer.com/images/licrespic/sugar%20crystals.jpgjpg

http://http://www.scientificpsychic.com/fitness/carbohydrates.htmlwww.scientificpsychic.com/fitness/carbohydrates.html

https://reader010.{domain}/reader010/html5/0621/5b2b5ad1e0190/5b2b5ae13d026.jphttps://reader010.{domain}/reader010/html5/0621/5b2b5ad1e0190/5b2b5ae13d026.jp

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