Determining the Amount of Sugar in Soft Drinks

Sodas vary widely in taste. There are colas, like Coke and Pepsi, which taste very different from citrus drinks like Mello Yello and Mountain Dew, which taste different from ginger ale... Even within a category such as colas or orange sodas, consumers claim to be able to distinguish different brands. These sodas vary slightly in their formulas, containing different amounts of the flavors used in combination to create their familiar tastes. One ingredient that varies widely in quantity is sugar.

Follow the procedure below to determine the amount of sugar in your favorite soft drinks.

Hypothesis:

Choose three non-diet sodas. (Suggestion: choose competing sodas, like Coke, Pepsi, and RC, or 7-Up, Sprite, and Slice, that fall into the same general category of flavor.) Have a taste test. Pour a cup of each soda. Taste them and compare the sweetness. Write down a short hypothesis stating which you think has the most sugar.

Activity/Procedure:

1. Choose a partner
2. Weigh six small (60-100 mL) dry beakers before beginning the experiment.
3. Pour 5 mL of sugar and 45 mL of water into a small beaker. (Note: Be careful to measure the exact amount so that the volume of your total solution is 50 mL)
4. Stir until the sugar is dissolved.
5. Weigh the beaker and subtract the dry weight to determine the mass of the solution.
6. Determine the density by using the formula d=m/v (density equals mass divided by volume).
7. Determine the reported density of sugar in each soda by reading the label located on the back of the soda.
8. Repeat the procedure above by using 10 mL of sugar and 40mL of water, and again using 15 mL of sugar and 35 mL of water Still make make sure it comes out to be an even 50mL.
9. Determine your density for 10 and 15 mL of sugar by using the formula d=m/v.
10. Graph your results using a ruler and your graph paper. (Graph the density vs. the amount of sugar)
11. Measure 50 mL of each soda (let the soda sit overnight so that it is flat) into the remaining three beakers.
12. Weigh the beaker and subtract the dry weight to determine the mass of each soda.
13. Determine the density of each soda using the formula d=m/v.
14. Using the graph that you have completed, determine the amount of sugar in your favorite sodas.
15. Compare the three results. Did they reflect the results of your taste test?

    (Note: Turn in graph sheets and all other work including questions stapled together.)

Questions:

1. Which of the soft drinks in this lab tasted the sweetest?

2. Which contained the most sugar? Was it the sweetest soda?

3. What the amount of sugar in the sweetest soda in the lab?

4. Do you think the results of this lab might have been different if carbonated water were used in the reference solutions, instead of plain water? How might they have changed?

5. How much soda do you drink a day? Approximately how much sugar is that?

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