INT1 Task 3 Exemplar

Does More Sugar Make Lemon Sauce Runny?

Project Design Plan

Cornstarch is a common thickening agent in cooking. Plant starch is made of a mixture of amylose and amylopectin. When heated in a water-based solution, the starch molecules can unwind and then form new hydrogen bonds with other starch molecules, making a network of long molecular filaments that can hold water molecules in a gel (Holmes, 2012). The Argo Cornstarch website warns that too much sugar can interfere with thickening (Argo, 2012).

Literature Review
There are many different ways to thicken liquids and thickening liquids has many applications. Many experiments have been done to test different thickening methods.

GVSoapCo tested 4 different substances to thicken homemade liquid hand soap: Xanthan Gum, Borax, Salt or Crothix. This experiment used the same soap recipe, substituting the different thickening agents. The experimenter then tested the thickness or runniness of the finished soap by spooning it up and drizzling it. This showed that the Crothix thickener made the thickest, smoothest soap, whereas the salt made the thinnest, runniest soap. While the spooning method was effective at showing the qualitative difference the thickening agent made, it didn’t produce quantitative measurements of the relative thickness (GVSoapCo, 2013).

Foy compared low sugar pectin with traditional pectin in making grape jelly. She reported that the traditional pectin made firmer jelly than the low sugar pectin. She determined this by qualitative observation rather than measuring the thickness. She did not test the effect of increasing the sugar in the recipe (Foy, 2013).

For this experiment, the amount of sugar in lemon sauce will be altered, making the sauce with the amount of sugar called for in the recipe, then with half as much sugar, then with twice as much sugar. The runniness of the three sauces will then be measured by allowing them to run down a tilted cookie sheet.

Experimental Design Steps
Lemon sauce will be made six different times as follows:
1. Sugar is mixed with cornstarch thoroughly in the sauce pan to make a homogenous mixture
a. First time, 2 Tablespoons cornstarch and ½ cup sugar
b. Second time 2 Tablespoons cornstarch and ¼ cup sugar
c. Third time 2 Tablespoons cornstarch and 1 cup sugar
d. Fourth time, 2 Tablespoons cornstarch and ½ cup sugar
e. Fifth time 2 Tablespoons cornstarch and ¼ cup sugar
f. Sixth time 2 Tablespoons cornstarch and 1 cup sugar

2. 3/4ths cup water is stirred into the sugar/starch mixture, a little at a time, to make a homogenous mixture

3. Heat is applied to the mixture (stove set at 4) stirring constantly.
4. When the mixture begins to boil, as noted by large bubbles rising to the top, the kitchen timer is started.
5. At 1 minute after boiling begins, the stove is turned off. 2 Tablespoons butter is added and the mixture stirred for 2 minutes.
6. 1/4th cup lemon juice is added and the mixture is stirred for 1 minute.
7. The mixture is transferred to a glass bowl.
8. All cooking materials are thoroughly washed and then rinsed in warm water, then in cold tap water to assure a consistent temperature for each repetition.
9. The sauces are allowed to set at room temperature, stirring occasionally until all three are the same temperature as measured by with the kitchen thermometer after mixing the sauces up with the wooden spoon to make sure they are homogenous.
10. The runniness of the sauces is then measured by letting them run down a cookie sheet and recorded. The average is calculated for sauces with the same sugar content.

Reasoning
Since typical recipes for lemon sauce call for ½ cup of sugar for every 2 Tablespoons of cornstarch, repeating the recipe with half as much sugar and twice as much sugar should give a good estimation of how important the sugar to cornstarch ratio is in the runniness of the sauce. Measuring all six sauces at once should be better than measuring them one at a time, since it will be easier to make sure all conditions are the same for all 6, except for time the sauces have set at room temperature, which can’t be avoided without a bigger kitchen and more assistants. By making sure they are all the same temperature and by stirring them up immediately before measuring, differences measured should be primarily due to the different sugar content.

Sequence of Events
The runniness of the sauce is determined by how far ½ teaspoon of the sauce would run down a cookie sheet tilted at approximately 5 degrees.
1. All sauces are determined to have reached the same temperature using the kitchen thermometer
2. ½ teaspoon of each sauce is placed on the cookie sheet, flat on the countertop, making note of which sauce is which. Sauces with the same sugar content are not placed beside each other to avoid bias from any variation in the surface of the cookie sheet.
3. The cookie sheet is gently propped up onto a pot lid, putting it at an angle of about 5 degrees.
4. The sauces are allowed to run down the sheet due to gravity for 2 minutes, as measured with a kitchen timer. At 2 minutes, the pot lid is removed gently and the cookie sheet placed flat again.
5. The length of the sauce’s trail in centimeters is measured from the top of where the sauce was placed to the furthest point it has run using the centimeter ruler. A wooden toothpick is placed at the bottom of the sauce run to point at the ruler so the ruler doesn’t have to touch the sauce. The measurements are placed in a table and the average run length of like sauces is calculated by adding the two lengths together and dividing by two.

Tools and Technologies
Corn Starch (Argo Brand)
Water
Granulated white sugar
Butter
Lemon Juice
Small Copper Sauce Pan
Wooden Spoon
6 Glass Bowls
Stove (Natural Gas)
Kitchen Timer (minutes and seconds)
Kitchen Thermometer (Degrees Fahrenheit)
Cookie Sheet
Wooden tooth picks measuring cups and spoons (Imperial measure)
Aluminum Foil
Centimeter ruler with millimeter demarcations

Variables
Independent variable:the amount of sugar added to the sauce
Dependent variable: the distance in centimeters ½ teaspoon of sauce runs down a tilted cookie sheet in 2 minutes.
Controlled variables: the amounts of cornstarch, lemon juice, butter and water. The cooking time. The temperature setting of the stove. The heating unit of the stove. The time boiling. The temperature of the sauce when the runniness is measured. The tilt angle of the cookie sheet.

Threat reduction to internal validity,
By thoroughly washing all the equipment between sauces and then rinsing everything in cold tap water, the experiment assures that contamination or temperature differences won’t interfere with the results. Using the same heating unit of the stove every time controls for any discrepancy between the dial setting and the actual heat produced. Measuring all the sauces at the same time on the same cookie sheet makes certain that the angle of tilt is the same for all. Waiting until all sauces are the same temperature keeps the temperature’s effect on runniness from interfering. By making each sauce twice and putting the sauces on different points on the cookie sheet, the experiment makes sure that variations in the cookie sheet surface don’t bias the experiment. By making each sauce twice, the experiment avoids measuring the effect of sitting time on runniness, since one high-sugar sauce will be made in the middle of the run and the other will be made at the end, for instance.

Hypothesis
The hypothesis of this experiment is that the more sugar in the recipe, the further the sauce will run down an inclined cookie sheet in 2 minutes, as measured in centimeters with the ruler. This hypothesis was based on the statement on the Argo website that too much sugar could decrease thickness.

Process of Data Collection

As predicted, the sauce made with 1 cup of sugar was much more runny than the sauce made with the amount of sugar called for in the recipe. While the sauce made with only 1/4th cup sugar felt thicker, no difference could be measured between this sauce and that produced by the unaltered recipe using the method described above. Indeed, neither the ¼ cup sauce or the ½ cup sauce ran down the cookie sheet any measurable distance in two minutes. Unexpectedly, the sauces with too much sugar made different-shaped puddles when they were placed on the cookie sheet. This may explain the differences in how far they ran.

Data Table: Runniness of sauces with different amount of sugar.
Sugar in the Recipe First Made Second Made Average run ¼ cup 2.5 cm 2.5 cm 2.5 cm
½ cup 2.5 cm 2.5 cm 2.5 cm
1 cup 5 cm 7.5 cm 6.25 cm

Appropriate Methods
The fact that the sauces with too much sugar ran so much further than the other two shows that 2 minutes at this angle was a good time to measure an increase in runniness. That the two high-sugar sauces ran a fairly different length might indicate that the way the sauce was placed on the cookie sheet might need to be controlled better, or perhaps the way the sauces were made needs to be more consistent. But the sauces with the same amount of sugar act more like each other than like the other sauces, so these methods are appropriate for detecting the effect of too much sugar on runniness. A longer time might be necessary to see any difference between the normal sauce and the sauce with too little sugar.

Results Graph above shows, no difference was detected between the sauces with ¼ cup sugar and the sauces with ½ cup sugar. Both ran an average of 2.5 centimeters, which was close to the distance covered just by placing the sauce on the cookie sheet. Essentially, they didn’t run at all. But the sauce with 1 cup of sugar did run. The average of the two was 6.25 cm, more than twice the average run of the other sauces..

Conclusion
Confirmation of Hypothesis
The results shown above confirm the hypothesis that increasing the amount of sugar in lemon sauce increases the runniness of the sauce. While decreasing the amount of sugar by half did not have a measurable difference in the runniness compared to the original recipe, doubling the amount of sugar produced a sauce that would run down a tilted cookie sheet an average of 6.25 centimeters in 2 minutes compared to 2.5 centimeters for the unaltered recipe.

Experimental Design as a Key Factor
The design of an experiment is essential in determining how reliable the results are. A well designed experiment needs to test a single independent variable. If the experiment alters more than one thing between test groups, it’s impossible to know what caused the any effect you might measure. Likewise, having a clear, objective way to measure any effect is important in the design of an experiment. The experimenter must be able to reliably determine if what was altered produced the predicted effect or not. This also depends upon controlling as many variables as possible. If random factors are allowed to enter the experiment, the experiment is not well designed and the results will be unreliable.

Replication
In order to replicate this experiment, it is important to measure all ingredients carefully and add them in the order called for in the directions. Since the acidity of the lemon juice might also affect the gel made by the cornstarch, being consistent with how that is added is particularly important for replicating the experiment. Being consistent with how the sauce is poured onto the cookie sheet is also important for consistent replication. Differences in elevation may change the temperature at which the sauce boils and this might change the exact distance measured by someone replicating this experiment at a higher or lower elevation, but the relative differences should still be replicable if other variables are appropriately controlled.

Evaluation of Validity
If others were to replicate this experiment, it would help determine if the experiment is valid. Scientist replicate experiments to determine their validity. When an experiment is repeated and the same results are measured, that gives a greater degree of confidence that the experiment is valid. The more times the experiment is replicated with the same results, the more confident we are in the validity. But if an experiment can’t be consistently replicated, this calls into question the validity of the experiment. The experimenters may have done the experiment right when this happens; there may simply be a variable that needs to be controlled that the scientists are unaware of. Reference List
Argo (2012). Frequently Asked Questions. Retrieved from http://www.argostarch.com/faq.html
Crocker, Betty (1996). Betty Crocker’s New Cookbook. New York, NY: Macmillan.

Foy (2013)Side by Side Comparison of Traditional and Low Sugar Pectin Recipe for Grape Jelly http://foyupdate.blogspot.com/2012/09/side-by-side-comparison-of-traditional.html GVSoap Co (2013) Comparison of Liquid Soap Thickeners http://www.youtube.com/watch?v=gM_zR42bOUA
Holmes, Zoe (2012). Starch. Retrieved from http://food.oregonstate.edu/learn/starch.html