The Jolly Rancher Experiment Illustrating the importance of Random Design in Experiments

Questions to Answer Why does gum or candy sometimes last longer than other times? Do the environmental conditions in your mouth effect how long the candy lasts? What factors in your mouth effect the longevity of gum or candy?

What is Known Gum and candy are flavored by sugar Liquid, like water or saliva, can only dissolve so much sugar = point of saturation Different drinks have different properties Sugar levels, pH level, carbonation, etc. According to the ADA (dentists) the two factors that lead to tooth decay (dissolving enamel) are sugar level and pH (acidity) of foods we eat…

What is Known pH (scale of 1-14) is a measure of acidity Everything has a pH or potential hydrogen Low pH (1-7) = acidic = sour or tart tasting High pH (7-14) = alkaline = bitter tasting Most drinks are 7.0 or lower because we don’t like bitter tastes Sugar levels vary in drinks Varies from 0 to 20 grams per serving So what are some sugar and pH levels of things we consume???

What is Known Liquid (8 oz serving) pH level Sugar level Stomach Acid 1.4 (reference) ??? Sunny Delight 2.4 (acidic) 20 g (high) Cranberry Juice 3.0 (acidic) 8 g (low) Chocolate Milk 6.8 (non-acid) 26 g (high) Distilled Water 7.0 (non-acid) 0 g (low)

What is Known Notice, most acidic drinks have at least some sugar to counter the tart acidic taste What about “7-Up”?? Actually named for being very non-acidic or pH levels “above 7” or “7-Up” That’s why mom said to drink it when you puke, because it neutralizes the stomach acid We can’t use it in our experiment because… Because it is carbonated. The other trial drinks are not carbonated and thus non-carbonated cannot be a constant.

Designing The Experiment Question: Do pH and sugar level of saliva affect the dissolving of hard candy? Hypothesis: Consuming drinks with a _______ pH and _______ in sugar will dissolve hard candy faster than other drinks. Independent Variable: Combinations of pH level and sugar Have the students write down the design of the experiment.

Designing the Experiment Treatments: 1-High pH-High Sugar=Milk 2-Low pH-Low Sugar=Cranberry Juice 3-High pH-Low Sugar=Water 4-Low pH-High Sugar=Sunny Delight Trials: # of students in class/ 4 treatments We will tally and analyze all Ag Sci classes data together for more trials Ex. 28 students in class = 7 trials per class

Designing the Experiment Dependent Variable: Amount of sugar dissolved in grams Constants: No talking Sucking time No biting Same amount of liquid Liquid swished for 10 seconds Same candy

Designing the Experiment What about the uncontrollable variables? sucking method, flavor of Jolly Rancher, breakfast foods, teeth brushing, DNA etc.??? That is why Random Design is so important We cannot control all variables, but having a large number of trials and a randomly designed experiment helps counter these

Procedures Prep 1- Using the Sharpie, write your name on the candy wrapper Prep 2- Unwrap the candy and set it on the wrapper- DO NOT EAT IT or throw away the wrapper Prep 3-Weigh your Jolly Rancher with the wrapper and record on your paper Prep 4-Get your assigned drink based on your playing card suit but don’t drink yet Jolly Ranchers usually weigh the same within .2 grams. If time is tight, you can omit this step and tell everyone the weight of their candy prio to sucking.

Procedures Step 1- Swish assigned treatment in your mouth but DO NOT swallow Step 2- Swish liquid for 10 seconds and swallow Step 3- As a class start sucking on candy at the same time Step 4- Suck Jolly Rancher without talking for 4 minutes

Procedures Step 5- Remove candies and allow them to dry on wrapper for 24 hours to remove saliva Step 6- Weigh candies with treatment groups to determine sugar dissolved This can be reported as a total for the treatment group, or as an average amount Should be consistent with other data Step 7- Organize and analyze data as a class, then combine classes to increase trials