How should customers take their Alka-Seltzer?The findings of 2-3 B

Variables tested

• Stirred vs. not stirred• Temperature of tablet• Volume of water• Substances• Surface Area• Temperature of water

Constants

• 50 mL of water• Distilled water• Room temperature tablet and water• no stirring• half tablet• stop the time when tablet itself has

stopped dissolving

What happens in an Alka-Seltzer reaction?

• Effervescence:• Citric acid and baking soda in the tablet go

through a chemical reaction• The final product is water, carbon dioxide, and

sodium citrate• The sodium citrate is dissolved in the water• That’s the gas we see being emitted from the

tablet.

Stirred vs. Not stirred (Group 1)

•Hypothesis: We believed that the Alka-Seltzer tablet would dissolve quicker as it was stirred faster

Data

Speed Trial 1 (s)

Trial 2 (s)

Trial 3 (s)

Average (s)

Standard Deviation

Not stirred

56.8 52.4 54.2 54.5 2.212088

Slow 45.4 46.9 44.6 45.6 1.167619

Medium 41.5 44.9 43.2 43.2 1.7

Fast 40.5 37.9 41.9 40.0 2.003331

Graphical Analysis

The graph shows that as the stirring speed increased, the time to dissolve decreased. Not stirred Slow Medium Fast

0

10

20

30

40

50

60

Time to dissolve stirred at a certain speed

Stirring Speed(setting)

Tim

e to

diss

olve

(s)

Analysis

• The data collected does accurately support the hypothesis in that the time to dissolve decreased as it was stirred faster.

• Experimental Difficulties• measuring exactly 50 mL of water• cutting exactly half a tablet• perfectly accurate timing

• Future Improvements• more accurate stopwatch• set of tablets equal to half a normal tablet• the same person timing and watching the tablet

dissolve

Temperature of tablet (Group 2)

•Hypothesis: The warmer the tablet, the quicker it will dissolve in the 50mL of water.

Data

Temperature of tablet (˚C) Time (s)

5.6 60.65

14 55

20.7 46.07

46 37.26

112 14

Graphical Analysis

The tablet with a greater temperature dissolves faster because the particles in the tablet are moving faster, causing a quicker reaction when coming in contact with water. 0 20 40 60 80 100 120

0

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20

30

40

50

60

70

Temperature of tablet vs. time to dissolve

Temperature (degrees Celsius)

Ti

me (seconds)

Analysis

• Overall, our hypothesis was correct that the greater the temperature of the tablet, the quicker the tablet would dissolve after coming in contact with the water.

• Experimental Errors• Amount of Water• Tablet not cut exactly in half• Don't know exactly when tablet is fully dissolved

• Ways to Improve• Use full tablet as constant to all are exact same

size

Type of Liquid (Group 3)

•Hypothesis: The Alka-Seltzer tablet will dissolve faster in other liquids than in distilled water, especially in a carbonated drink.

Data

Type of liquid

Time (trial 1) (s)

Time (trial 2) (s)

Time (trial 3) (s)

Average (s) Standard Deviation

Distilled Water

48.4 46.8 53.2 49.5 2.719477074

Coffee 175.7 180 171.2 176 3.592894222

Diet Pepsi 55.3 61.6 57.2 58 2.638602324

Cranberry Juice

62.8 56.9 68.9 62.9 4.899206285

Graphical Analysis

The graph shows the time for the tablet to dissolve in different liquids. Controlled dis-

tilled water Coffee Diet Pepsi Cranberry

juice

0

20

40

60

80

100

120

140

160

180

200

Alka-Seltzer dissolving time in liquids

Type of Liquid

Time to Dissolve

(s)

Analysis

• The data that we collected with this experiment did not support our hypothesis that the controlled type of liquid would dissolve the tablet the slowest.

• Experimental Errors•  Timing exactly• Correct measurements of liquids and tablets• Warming the soda took away the carbonation

• Future Improvements•  Whole tablets, no error on cutting• More accurate timer• The liquids all at room temperature before experiment started

Volume of water (Group 4)

•  Hypothesis: We believe that as the amount of water increases, the Alka-Seltzer tablets will dissolve quicker.

Data

Amount of water (mL)

Time (trial 1) (s)

Time (trial 2) (s)

Time (trial 3) (s)

Average (s)

Standard Deviation

20 65.7 58.7 69.8 64.7 5.613

50 52.8 51.4 57.6 53.9 3.252

100 49.1 52.1 50.8 50.7 1.504

200 54.6 50.8 48.2 51.2 3.219

Graphical Analysis

The graph shows the relationship between the amount of water and average dissolving time.

20 50 100 2000

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20

30

40

50

60

70

Dissolving Time in Different Amounts of Water

Amount of Water (mL)

Tim

e (s

)

Analysis

• The results we found roughly supported our hypothesis that as we got more water, the tablets would dissolve quicker. But really, the difference in average dissolving time was ten seconds at the most -- so there wasn't any significant changes to dissolving time as we changed the amount of water.

• Experimental Errors• When we ended timing ("when the tablet was fully dissolved") had a

lot of room for judgment and human error.• Our measurements of the amount of water for our tests could be

slightly off.• We might of not cut the tablets perfectly in half therefore changing a

variable (size of tablet)• Room for Improvement• We could have measured all other variables so we were sure they met

control conditions. (i.e. temperature of water, size of tablet)• We could have been more accurate timers.

Surface Area of tablet (Group 5)

Hypothesis - We predict that the Alka-Seltzer tablet will dissolve faster when crushed into a powered form and then pouring the distilled water.

Data

Graphical AnalysisHalf Tablet 0.25 Tablet 0.125 Tablet Powder After Powder First

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60

70

Dissolving Time For Different Size Alka-Seltzer Tablets

Size of Tablet

Tim

e to

Diss

olve

(s)

Analysis

• The data we collected does support our hypothesis which was that putting the crushed tablet first and then pouring the water would decrease the time it took to dissolve the tablet.

• Experimental Error• Accuracy of measuring 50 ML into a beaker• Cutting a tablet into halves, quarters, and eights, and

crushing the tablet• Accurate timing

• Future Improvements• More accurate stopwatch• Using whole tablets• Having the same person look watching the tablet dissolve

Temperature of Water (Group 6)

• The tested variable was the temperature of the water. We used the control temperature (19.3 ˚C), hot water (30.3 ˚C) and cold water (8.6 ˚C)• Hypothesis: The Alka-

Seltzer tablet would dissolve the fastest in the hottest water.

Data

Temperature of Water (o C)

Time (Trial 1) (s)

Time (Trial 2) (s)

Average (s) Standard Deviation

19.3 60.4 64.0 62.2 1.8

8.6 109.7 108.9 109.3 0.4

30.3 36.4 39.9 38.15 1.75

Graphical Analysis

• Lowest temperature: highest time (~110 seconds)

• Room temperature:

•  average time (~62 seconds)

• Highest temperature: lowest time (~38 seconds)

19.3 8.6 30.30.0

20.0

40.0

60.0

80.0

100.0

120.0

Temperature of Water vs. Dissolving Time

Temperature of Water (˚C)T

ime

(s)

Analysis

• We found that the higher the temperature of water, the quicker the tablet dissolves in the water.

• This matches our hypothesis completely.• There was only one major difficulty in our

experiment. It was very difficult to get the water to be at the same temperature for two separate trials. 

• Things we could change for future experiments include making our temperatures precise, and also experiment with a greater range of temperatures (i.e. 10 ° C, 20 ° C, Room Temperature, 30 ° C, etc.)

Conclusion

• Through the results of this experiment, we have found that the most efficient method to use Alka-Seltzer would be using the fastest results from all experiments, provided they are safe and practical.

• One should:• Stir it fast (difference of 14.5 seconds)*• Make it a powder before putting the tablet in (36.3 seconds)• Put it in hot water (24 seconds)• Put it in water**• Put it in a large amount of liquid (13.5 seconds)

*in comparison to control**water was the control