Guided Practice
Students will complete an activity to investigate the reaction time of one effervescent tablet in
different temperatures of water. This activity can be set up in a variety of ways.
For example:
1. One group may investigate the cold water, the second group the hot water, and the third group
the room temperature water.
2. Each group may investigate all three temperatures of water, but with only one thermometer if
you have limited resources.
3. Each group may investigate all three temperatures of water simultaneously for multiple trials
which requires more resources per group.
Other things to consider:




There are multiple ways to organize this experiment and it is recommended to plan which best
fits the needs of the students, teacher, and classroom environment.
Also, consider how to organize the safety equipment and disposal prior to the activity. The
water with dissolved tablets can be flushed down the sink if available. Also, a disposal
container may need to be provided. Students will need to wear goggles and use appropriate
precautions for handling hot water.
Students will need access to hot water, but not hot enough to scald. Also, access to ice water
or refrigerated water is needed.
If technology is available, temperature can be recorded using probes. It is recommended to use
spreadsheet software to record, graph, and analyze data if available although not necessary.
Grid paper has been provided as a resource.
Problem
Effervescent tablets can used to treat upset stomachs. When taken in powder form they
produce a lot of carbon dioxide gas which can cause further discomfort. When dissolved in
water, this gas is released prior to taking the medicine and is also taken more easily as a liquid.
Present in most tablets is acetylsalicylic acid, a common as a pain reliever, but this is not part of
the chemical reaction being observed.
Your task is to investigate how to reduce the time it takes to dissolve the tablets, so that a
person may receive their medicine more quickly for comfort. It has been rumored that water
temperature will have an effect. You will need to investigate the problem, analyze the data,
and report your supported conclusions.
Materials:
Thermometers (digital recommended)
Effervescent tablets
 can often be purchased as generic and in bulk in the pharmacy departments
 quantity depends on how many trials each group will complete
© Copyright 2014 – all rights reserved www.cpalms.org
Containers to dissolve tablets
 Beakers if available
 Also, clear plastic cups can be used, but may result in more spills. If using, clear plastic
cups it may be necessary to consider having a cup holder. Some suggestions are a
muffin tin which can be purchased at thrift stores inexpensively or paper cup holders
from a local fast food restaurant.
Safety goggles
Water (at least three different temperatures)
Procedure
1. Please gather the materials and discuss the procedures prior to starting. These reactions can
occur very quickly. In order to collect accurate data, it should be decided who is doing each
part.
2. Choose one of the water temperature and measure out _________ ml of water. Measure the
temperature on your data sheet.
3. Place one effervescent tablet and measure the time for complete reaction to occur. Record the
time on your data sheet.
4. Repeat step 2 for each of the temperatures provided for each of the trials required.
Sample data table
Water (_____oC)
Water (_____oC)
Water (_____oC)
Trial 1
______________(s) ______________(s) ______________(s)
Trial 2
______________(s) ______________(s) ______________(s)
Trial 3
______________(s) ______________(s) ______________(s)
Average
Analyze data
Teacher notes:
1. This portion can be accomplished in a variety of ways to accommodate the teacher,
students, and time.
a. Graph and discuss in class discussion
b. Graph and discuss in cooperative groups (recommended)
c. Also, analyzing the slopes and best line fit to determine the formula could offer
students with higher math abilities more rigor.
d. Use technology to record and analyze data if available
© Copyright 2014 – all rights reserved www.cpalms.org
1. Average the temperature of each trial by adding up the total trials and dividing by the
number of trials.
Average = Trial 1 + Trial 2 + Trial 3 + … + Trial n
Number of trials (n)
2. Average the time of each trial by adding up the total trials and dividing by the number of
trials.
3. Graph the temperature versus time.
Conclusion
Discuss the relationship between temperature and the reaction time for this chemical reaction.
Following the relationship, record how your data confirms the relationship you concluded. Be
specific and include all of your data.
Students should record that the reaction time decreased as the as the temperature increased.
Students should use their data from the activity to support their findings.
© Copyright 2014 – all rights reserved www.cpalms.org