How should customers
take their Alka-Seltzer?
The findings of 2-3 B
• Stirred vs. not stirred
• Temperature of tablet
• Volume of water
• Substances
• Surface Area
• Temperature of water
Variables tested
• 50 mL of water
• Distilled water
• Room temperature tablet and water
• no stirring
• half tablet
• stop the time when tablet itself has
stopped dissolving
Constants
• 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.
What happens in an AlkaSeltzer reaction?
• Hypothesis: We
believed that the
Alka-Seltzer tablet
would dissolve
quicker as it was
stirred faster
Stirred vs. Not stirred
(Group 1)
Speed
Trial 1 (s) Trial 2 (s) Trial 3 (s) Average
(s)
56.8
52.4
54.2
54.5
Standard
Deviation
2.212088
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
Not
stirred
Slow
Data
Time to dissolve stirred at a certain speed
60
50
Time to dissolve(s)
The graph
shows that as
the stirring
speed
increased, the
time to
dissolve
decreased.
40
30
20
10
0
Not stirred
Slow
Medium
Stirring Speed(setting)
Graphical Analysis
Fast
• 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
Analysis
• Hypothesis: The warmer the
tablet, the quicker it will
dissolve in the 50mL of water.
Temperature of tablet
(Group 2)
Temperature of tablet (˚C)
Time (s)
5.6
60.65
14
55
20.7
46.07
46
37.26
112
14
Data
70
60
T
i
m 50
e
40
s
e
c 30
o
n 20
d
s
10
(
)
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.
Temperature of tablet vs. time to dissolve
0
0
20
40
60
80
Temperature (degrees Celsius)
Graphical Analysis
100
120
• 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
Analysis
• Hypothesis: The
Alka-Seltzer tablet
will dissolve faster
in other liquids
than in distilled
water, especially in
a carbonated drink.
Type of Liquid (Group 3)
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
Data
The graph
shows the
time for the
tablet to
dissolve in
different
liquids.
Alka-Seltzer dissolving time in liquids
200
180
160
140
120
Time to 100
Dissolve 80
60
(s)
40
20
0
Controlled
distilled water
Coffee
Diet Pepsi
Cranberry juice
Type of Liquid
Graphical 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
Analysis
• Hypothesis: We
believe that as the
amount of water
increases, the AlkaSeltzer tablets will
dissolve quicker.
Volume of water (Group 4)
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
Data
70
60
50
Time (s)
The graph
shows the
relationship
between the
amount of
water and
average
dissolving time.
Dissolving Time in Different Amounts of
Water
40
30
20
10
0
20
50
100
200
Amount of Water (mL)
Graphical 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.
Analysis
Hypothesis - We predict that the Alka-Seltzer tablet will
dissolve faster when crushed into a powered form and then
pouring the distilled water.
Surface Area of tablet
(Group 5)
Data
Dissolving Time For Different Size Alka-Seltzer Tablets
Time to Dissolve (s)
70
60
50
40
30
20
10
0
Half Tablet
0.25 Tablet
0.125 Tablet
Powder After
Size of Tablet
Graphical Analysis
Powder First
• 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
Analysis
• 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 AlkaSeltzer tablet would dissolve
the fastest in the hottest
water.
Temperature of Water
(Group 6)
Temperature Time (Trial
of Water
1) (s)
(o C)
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
Data
Temperature of Water vs. Dissolving
Time
120.0
100.0
80.0
Time (s)
• Lowest
temperature:
highest time
(~110 seconds)
• Room
temperature:
• average time
(~62 seconds)
• Highest
temperature:
lowest time (~38
seconds)
60.0
40.0
20.0
0.0
19.3
8.6
Temperature of Water (˚C)
Graphical Analysis
30.3
• 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.)
Analysis
• 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)
Conclusion
*in comparison to control
**water was the control