Introduction: (Initial Observation)
Volcano is an opening in the earth’s crust through which molten lava, ash, and gases are ejected. Some volcanoes are on dry land and some others are under water in deep oceans. Some islands are entirely formed by volcanic material. Volcanoes are constantly changing the landscape on the earth.
As the world’s population grows, more and more people are living in potentially dangerous volcanic areas. Volcanic eruptions continue–as they have throughout history–posing ever-greater threats to life and property.
In this project you make a model of a volcano and display the eruption process and and release of lava or magma.
Information about volcano models are available at:
Inside the earth, hot magma and gasses look for weak spots to push through. Magma and gasses will push up through not only the main conduit, but also through any cracks (vents) it can find. Once magma (molten rock) leaves the inner earth and finds its way to land, then we call it lava.
What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.
We want to see what happens that a volcano erupts. A review of current and past volcano eruptions indicates some kind of under ground pressure that forces the lava out of a volcano. Can we simulate such underground pressure?
Also find out what ratio of vinegar/ baking soda produces the highest amount of gas for your volcano experiment.
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.
We use the reaction of vinegar and baking soda to produce carbonic gas and use it to create a display similar to a real volcanic eruption.
The independent variable (also known as manipulated variable) is the ratio of vinegar to baking soda.
The dependent variable (also known as responding variable) is the amount of gas produced by the reaction.
Control variable is the ambient temperature (room temperature).
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.
Baking soda and Vinegar can produce enough gas to simulate a volcanic eruption. This is a sample hypothesis for the ratio of the vinegar to baking soda.
The highest amount of gas will be produced when equal amounts of baking soda and vinegar are used
Design an experiment to test each hypothesis or construct a model to display how a volcano is erupted when the pressure of gases push out molten lava.
Make a Volcano model that can erupt. Eruption can be simulated by a chemical reaction between vinegar and baking soda. Model can be constructed using paper, aluminum foils and clay.
We mix baking soda and vinegar in a plastic bottle in different ways and see which combination and rates of mixture will create the best model for a volcanic eruption.
When we find the best setup and combination, we cover the bottle by papers, aluminum foil, clay and other material to make it look like real volcano. So in the center of our volcano will be a bottle with chemicals that create the eruption.
In our first experiment we use a small cup of vinegar and start adding baking soda to that. Initially baking soda will release gas as soon as it gets to the vinegar. But if we continue, at some point there will be no gas any more. In this way we record the amount of baking soda and vinegar that create gas with each other.
In the second experiment we check to see which should be at the bottom to create a better and faster reaction, baking soda or vinegar.
In the third experiment we add some liquid detergent and some red food coloring to vinegar before reaction with baking soda. Liquid detergent may help the foams last longer and food coloring gives a better look to the erupting volcano. You may also add some flour to the baking soda that you are using to create a more viscose lava.
When the chemical composition is experimented successfully, we mount the bottle on the center of a card board and cover it with newspaper and aluminum foil to look like a real volcano.
Baking soda and vinegar are frequently used for volcano projects simply because they are easily accessible and less dangerous. Personally I prefer other methods that create better display and of course have more risk.
In one example you fill up your volcanic cone with Ammonium bichromate and light it up at the display. Ammonium bichromate is a flammable solid and burns very similar to a volcano. It has a nice display and creates a lot of smoke. Use heavy aluminum foil to cover your card board and construct your cone and do your display in an open area. If you want to do this, make your volcano as small as possible (about 2″ high).
The other method that I like is using a solid acid instead of vinegar. Citric acid for example, specially if you get it in powder form can be a good choice. You can mix it dry with baking soda, paint powder such as Iron oxide (red) and detergent powder. So when you are ready to do your demonstration you just add some water and reaction starts.
Compare the number of volcanic eruptions in the past seven years. Draw a graph to show how has the number of annual eruptions changed in the past seven years.
When a volcano is restless, scientists collect and record different data about the volcano. Such data include the earthquakes, ground deformation, and sulfur dioxide gas around each specific volcano. By comparing data from several sources, scientists are able to get a more complete picture of what is happening under the ground than they would by analyzing only one data type. Collected data about volcanic activities can be found on the Internet and Geological publications.
For a list of current volcanic activities search the Internet or visit http://volcano.und.edu/vwdocs/current_volcs/current.html. A copy of this data ia also available here. You can compile the data provided in this website to determine specific regional volcano information and enter them in a table. You can then use such table to draw a graph. (You may also try http://www.swvrc.org/research.htm for volcano data)
Compile the data in the current volcanic activities table and determine how many volcanic eruptions has happened in each of the last seven years. Record your data in the following table. You have choice to select world wide volcanoes or just the volcanoes in one continent.
|Year||Number of Volcanic Eruptions|
Use the above table to make a bar chart.
In this experiment you will try to find out what ratio of vinegar and baking soda will produce the most amount of gas.
- Get a small measuring spoon or measuring cup. The cap of a soda bottle may be used as a measuring cup.
- Get 9 Styrofoam cups and label them as vinegar. Also number them from 1 to 9. Add one spoon of vinegar in the cup number 1. Add two spoons of vinegar in the cup number 2. Add three spoons of vinegar in the cup number 3. Continue until you add 9 spoons of vinegar to the cup number 9.
- Get 9 empty soda bottles. Label them from 1 to 9. Add 9 spoons of baking soda in the soda bottle number 1. Add 8 spoons of baking soda in the soda bottle number 2. Add 7 spoons of baking soda in the soda bottle number 3. Continue until you add 1 spoon of baking soda in the soda bottle number 9.
- Transfer the vinegar from the cup number 1 to a balloon and then place the balloon over the soda bottle number 1. Heavy vinegar will hold the balloon hanging and no vinegar will enter the bottle at this time. Wrap a cotton string on the bottle neck to hold the balloon securely. Make a knot. No gas must be able to leak from the bottle.
- Repeat this with all cups and all soda bottles that have the same number.
- Carefully start to lift the balloons one at a time so the vinegar in the balloon will enter the bottle and produce gas. Produced gases will inflate the balloons. Measure the circumferences of all balloons and record them in your results table.
- Your results table may look like this:
|Vinegar||Baking soda||Balloon circumference||Balloon radius||Gas volume|
|1 Unit||9 Unit|
|2 Unit||8 Unit|
|3 Unit||7 Unit|
|4 Unit||6 Unit|
|5 Unit||5 Unit|
|6 Unit||4 Unit|
|7 Unit||3 Unit|
|8 Unit||2 Unit|
|9 Unit||1 Unit|
The “Unit” may be measuring spoon; however, if you have access to a gram scale, it is best if you use one gram as your unit. In this way 4 Unit vinegar will really be 4 grams of vinegar.
To calculate the radius of a spherical balloon divide the circumference of the balloon by 6.28.
The volume of the balloon is =4/3¶r3
To calculate the volume of the balloon multiply 4/3 x 3.14 x radius x radius x radius. Write the volume of the balloon for each ratio in the gas volume column.
Materials and Equipment:
- Plastic bottle (Wide mouth, 5 to 9 inches tall)
- Baking soda
- Liquid detergent
- Food coloring (red)
- Aluminum foil
- Masking tape
Results of Experiment (Observation):
Experiments showed that the reaction between baking soda and vinegar creates some gas, but it is not fast enough to create a violent reaction and simulate a real volcanic reaction. We can stir or shake the mixture to create more gas, but it is not very realistic to shake a volcano to cause eruption.
To speed up the reaction we must fill up the plastic bottle with baking soda while leaving an empty hole in the center of that for adding vinegar.
This hole should be as wide as possible so your bottle will hold more vinegar than baking soda. To do this you need to make paste of baking soda.
Take one spoon liquid detergent, two spoons water, a few drops of food coloring and start adding baking soda slowly while mixing. Continue adding baking soda until you get a sticky paste. If your bottle is very small and your volcano is small too, this should be enough. For larger bottles you may need to repeat this part to make more paste. Apply a thin layer of this paste to the inner sides of your bottle (about 1/4″ tick).
The reason that we add liquid detergent is that bobbles are unstable and disappear very fast. Liquid detergent will make bubbles last for a few seconds.
Do this a few times and add vinegar to see how much foam comes out. After a few experiments you will be ready for your final product.
When your bottle is ready for final volcano, take a card board and using a masking tape secure the bottle in the center of the card board.
Before you start building your volcanic mountain around the bottle, you may also want to use some glue or masking tape around the neck of the bottle. This will prevent the foam from going inside your mountain.
You can almost use anything that can look like a mountain to cover your bottle. I used some packing paper and cut a cross on the center of that to make it easier to be attached to the neck of the bottle.
Cover the bottle with your mountain material such as paper or aluminum foil and paint it. Since my paper was not large enough, I has to use some extra magazine paper to give more body to the mountain.
Before painting, cover the the bottle with something to make sure that paint will not enter the bottle. I used spray paint, but you can use any latex paint as well. (Don’t add water).
I painted my volcano in the backyard, spray paints release harmful fumes and it’s better not to use them inside a building. While the paint was still wet, I also spread some sand to make it more natural. Paint will act like a glue and holds sand in place.
When your volcano is ready and it is your turn to display, fill up a small bottle or a test tube with vinegar and pour it in to your volcano. The eruption will start in a few seconds and lasts for a few minutes.
Remember you can do it only once and when the volcano erupts, it gets wet and you can not repeat your display unless you build everything from the beginning.
Final display that will last only a few seconds may look like this. As you notice I did not use food coloring and my lava is white. Also I used black color to paint the mountain that is not the best choice. If you have enough time for your project, you may use multiple colors and food coloring to get a better display.
Number of worldwide eruptions from 1989 to April 4, 2004
Calculate what ratio of baking soda and vinegar produce the most gas.
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.
The pressure of underground gases in a volcanic mountain will force the molten material out of the volcanic mountain.
Related Questions & Answers:
Q. How can we make a volcano that errupts more than once?
A. Instead of attaching the bottle to the base board, make and attach a cylinder from heavy paper that can hold the bottle. In this way you will be able to remove the bootle for refill or just use a second bottle that you have already prepared to repeat the erruption test.
When you do one eruption experiment, your volcano will get wet. So for multiple eruptions make your volcanic mountain from more durable material. Heavy paper with lots of paint can resist a few tests, but for more tests, make your volcanic mountain from plastics, aluminum foil, wood or even chalk (Plaster of Paris) that will be much heavier.
If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.
If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.
Visit your local library and find books related to volcano and the earth science (geology). Review and list such books as your references (bibliography) in addition to this website and other Internet resources.
Following are some Internet resources:
Volcano Paper Model
To make a volcano paper model, print this page and follow the instructions. You may enlarge this page by a copy machine and print it in heavy paper for better results.
You may also do your own drawing and paint it as well. To print only the picture, high-light it with mouse then click on “print” and choose “selection” and click “ok”.