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Balloon Race (The Effect of Temperature on the Rate of Reaction).

Balloon Race (The Effect of Temperature on the Rate of Reaction).

Introduction: (Initial Observation)

All chemical reactions lead to production of at least one new substance that can be gas, solid or liquid. After each process we can measure the weight or volume of the final product to know how much product is produced. So if we want to know the effect of temperature on the rate of reaction, we can simply repeat the reaction at different temperatures, but for a controlled period of time and finally compare the amount of products.

When the product is a gas, it is usually harder to do such a final measurement because gases are usually mixed with air, water vapor or other gases that need to be filtered.

In this project we intend to compare the rate of a gas producing reaction using balloons. The idea is that a higher rate of reaction results a higher rate of gas production resulting a higher rate of balloon inflation. For example the rate of formation of CO2 (g) from the reaction of Alka-Seltzer tablets with water* at different temperatures is easily observed by comparing the rates of inflation of balloons attached to the flasks in which the reactions are carried out.

* It is not really a reaction with water. Alka-Seltzer already contains a solid acid and a solid carbonate. I think that solid acid is citric acid and carbonate is sodium bicarbonate or baking soda. These two solid chemicals can not react unless water is present. So water is just a catalyst here. The actual reaction is the reaction of an acid and a carbonate.


This project guide contains information that you need in order to start your project. If you have any questions or need more support about this project, click on the “Ask Question” button on the top of this page to send me a message.

If you are new in doing science project, click on “How to Start” in the main page. There you will find helpful links that describe different types of science projects, scientific method, variables, hypothesis, graph, abstract and all other general basics that you need to know.

Project advisor

Information Gathering:

Find out about chemical reactions. Read books, magazines or ask professionals who might know in order to learn about the factors that affect the rate of a chemical reaction. Keep track of where you got your information from.

Following are some of the information you may find.

Bicarbonate and hydrogen ions, produced when Alka-Seltzer dissolves in water, react according to the following equation:

HCO3-(aq) + H+(aq) —-> H2O (l) + CO2 (g)

Increasing the temperature increases the rate of reaction because at the higher temperature, a greater percentage of ions in the sample have energy greater than the required activation energy for the reaction. The observed rate of inflation of the balloons, which is shown to be related to the temperature at which the reaction takes place, is a measure of the rate of formation of carbon dioxide gas.

See more information

Question/ Purpose:

The purpose of this demonstration is to show the effect of temperature upon the rate of a gas producing reaction such as the reaction of an acid and a carbonate.

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.

Controlled variables are all other factors that may affect the rate of reaction such as:

    • Type and concentration of all reactants
    • Size and shape of reactor (bottle)
    • Light

Independent variable also known as manipulated variable is the temperature.

Dependent variable is the rate of reaction indicted by the rate of production of carbon dioxide.


Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis. Following is a sample hypothesis:

    • In chemical reaction of citric acid and carbonates, the rate of reaction will increase by the increase of temperature.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”


    1. You may need to get some help during this experiment.
    2. Fill one flask about half way with hot tap water. Add an equal volume of room temperature tap water to the second flask and an equal volume of cold tap water to the third.
    3. Practice putting the balloon over the mouth of the flask.
    4. Break three Alka-Seltzer tablets into comparable size pieces.
    5. Add one broken tablet to each flask.
    6. Immediately put a balloon over the mouth of each flask.
    7. Note the rate of balloon inflation.
    8. Compare the sizes of the inflated balloons after certain amount of time or when the reaction stops to demonstrate that only the rate of reaction is affected, not the final amount of product.
    9. Solutions may be flushed down the drain with water.

Record the result of your experiment in a table like this.

Production of CO2 in X minutes Hot Water Room Temperature water Cold Water
Balloon Volume
Balloon Diameter
Balloon height

Note that gas in balloon is under pressure, so actual volume of gas in standard pressure is more than the balloon volume.

Make a graph:

A graph is a visual presentation of your results and a valuable addition to your display board. Make a graph with 3 vertical bars. Each bar will be for one of the temperature ranges you test. Name the bars as “Hot”, “Room temp.” and “Cold”.

The height of each bar will be the height of the balloon it represents.

You may make similar bar graphs based on the balloon diameter or the balloon volume.

Safety goggles are recommended.

You may perform the same experiment using vinegar instead of water and baking soda instead of Alka-Seltzer. This can be messy, so do a few tests in smaller scale first. If the vinegar is very strong, you will get a lot of vinegar and baking soda entering the balloon in the form of foam. Balloon may explode and make a mess out of your experiment room.

Materials and Equipment:


Alka-Seltzer tablets
tap water – hot, room temperature, and cold


balloons (previously blown up to stretch them)
125-mL Erlenmeyer flasks*
chemical scoops, spatulas or spoons

*Modification: In place of Erlenmeyer flasks, 10-12 oz. soda bottles may be used.

Results of Experiment (Observation):

Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.

Record the result of your experiment in a table like this.

Production of CO2 in X minutes Hot Water Room Temperature water Cold Water
Balloon Volume
Balloon Diameter
Balloon height

Note that gas in balloon is under pressure, so actual volume of gas in standard pressure is more than the balloon volume.


  1. Measure the circumference of the balloon.
  2. Calculate the radius of a spherical balloon by dividing the circumference of the balloon by 6.28.
  3. Calculate the volume of the balloon using the formula volume=4/3śr3

In the above formula r is the radius, r3 means r x r x r, and ś = 3.14

To calculate the volume of the balloon multiply 4/3 x 3.14 x radius x radius x radius. For example if the circumference of a balloon is 32 inches, you divide 32 by 6.28 to get 5 as the radius of the spherical balloon. Then the volume will be 4/3 x 3.14 x 5 x 5 x 5 = 523 cubic inches.

Write the volume of the balloon in the “CO2 amount” column of your results table.


If r or radius is in inches, the volume will be in cubic inches. If r is in centimeters, the volume will be in cubic centimeters.

Summary of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.


Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

Related Questions & Answers:

What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.

Possible Errors:

Check balloons before doing the demonstration to be sure that they will inflate with the pressure generated.

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