Introduction: (Initial Observation)
Carbon dioxide has a high commercial value and is used in many different industries. In liquid and solid form known as dry ice, carbon dioxide is an important refrigerant, especially in food industry, where they are used during the transportation and storage of ice-cream and other frozen foods. Carbon dioxide is used to produce carbonated soft drinks and soda water.
Carbon dioxide is often used as an inexpensive, non-flammable pressurized gas. Life jackets often have canisters of carbon dioxide for quick inflation.
Steel capsules are also sold as supplies of compressed gas for airguns, paintball markers, and for making seltzer. Rapid vaporization of liquid CO2 is used for blasting in coal mines.
Liquid carbon dioxide is a good solvent for many organic compounds, and is used to remove caffeine from coffee. It has begun to attract attention in the pharmaceutical and other chemical processing industries as a less toxic alternative to more traditional solvents.
In the theater, dry ice is used to produce fog as a special effect: when dry ice added to water, the evaporating mixture of CO2 and cold humid air condenses as a fog.
Traditionally, the carbonation in beer, yogurt drink, and sparkling wine happen through natural fermentation, but some manufacturers carbonated these beverages artificially. The carbon dioxide that cause dough to rise is also formed by natural fermentation within dough. Fermentation is is one of the methods that may be used to produce carbon dioxide.
In this project you will use fermentation to produce carbon dioxide. You will also observe and record the rate of CO2 production and study at least one condition that may affect the rate of CO2 production. Following are some of the factors that you may study:
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- Effect of temperature on production of carbon dioxide by fermentation.
- Effect of CO2 concentration on the production of CO2.
Information Gathering:
Find out about carbon dioxide properties and how it is used in different industries. Study about the methods of producing carbon dioxide and how animals and some micro organisms produce carbon dioxide.
Read books, magazines or ask professionals who might know about the factors that may affect production of carbon dioxide by animals and some microorganisms.
Keep track of where you got your information from.
Following are samples of gathered information online.
CARBON DIOXIDE
Carbon dioxide, CO2, is one of the gases in our atmosphere, being uniformly distributed over the earth’s surface at a concentration of about 0.033% or 330 ppm. Commercially, CO2 finds uses as a refrigerant (dry ice is solid CO2), in beverage carbonation, and in fire extinguishers. In the United States, 10.89 billion pounds of carbon dioxide were produced by the chemical industry in 1995, ranking it 22nd on the list of top chemicals produced. Because the concentration of carbon dioxide in the atmosphere is low, it is not practical to obtain the gas by extracting it from air. Most commercial carbon dioxide is recovered as a by-product of other processes, such as the production of ethanol by fermentation and the manufacture of ammonia. Some CO2 is obtained from the combustion of coke or other carbon-containing fuels.
Animals all have some sort of respiratory system. You see, in order to make ATP through cellular respiration, we need both sugar and oxygen. Animals obtain oxygen using the respiratory system. Then, when cellular respiration has occurred and ATP was made, that process created carbon dioxide and water as waste. The carbon dioxide (CO2) is a gas, and it gets released from animal bodies through the respiratory system. The respiratory system is just a body system designed to bring in oxygen and release carbon dioxide, all for use in cellular respiration.
chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. It does not burn, and under normal conditions it is stable, inert and nontoxic. It will however support combustion of magnesium to give magnesium oxide and carbon. Although it is not a poison, it can cause death by suffocation if inhaled in large amounts. It is a fairly stable compound but decomposes at very high temperatures into carbon and oxygen. It is fairly soluble in water, one volume of it dissolving in an equal volume of water at room temperature and pressure; the resultant weakly acidic aqueous solution is called carbonic acid. The gas is easily liquefied by compression and cooling. If liquid carbon dioxide is quickly decompressed it rapidly expands and some of it evaporates, removing enough heat so that the rest of it cools into solid carbon dioxide “snow.” A standard test for the presence of carbon dioxide is its reaction with limewater (a saturated water solution of calcium hydroxide) to form a milky-white precipitate of calcium hydroxide.
Carbon dioxide occurs in nature both free and in combination (e.g., in carbonates). It is part of the atmosphere, making up about 1% of the volume of dry air. Because it is a product of combustion of carbonaceous fuels (e.g., coal, coke, fuel oil, gasoline, and cooking gas), there is usually more of it in city air than in country air. The natural balance of carbon dioxide in the atmosphere is growing from its stable level of 0.13% to a predicted 0.14% by the year 2000. It is anticipated that this extra carbon dioxide will fuel the greenhouse effect, warm the atmosphere, and further disrupt the natural carbon dioxide cycle.
In various parts of the world–notably in Italy, Java, and Yellowstone National Park in the United States–carbon dioxide is formed underground and issues from fissures in the earth. Natural mineral waters such as Vichy water sparkle (effervesce) because excess carbon dioxide that dissolved in them under pressure collects in bubbles and escapes when the pressure is released. The chokedamp of mines, pits, and old, unused wells is largely carbon dioxide. Carbon dioxide is a raw material for photosynthesis in green plants and is a product of animal respiration. It is also a product of the decay of organic matter.
Carbon dioxide has varied commercial uses. Its greatest use as a chemical is in the production of carbonated beverages; it provides the sparkle in carbonated beverages such as soda water. Formed by the action of yeast or baking powder, carbon dioxide causes the rising of bread dough. The compound is also used in water softening, in the manufacture of aspirin and lead paint pigments, and in the Solvay process for the preparation of sodium carbonate. In some fire extinguishers carbon dioxide is expelled through a nozzle and settles on the flame, smothering it. It also has numerous nonchemical uses. It is used as a pressurizing medium and propellant, e.g., in aerosol cans of food, in fire extinguishers, in target pistols, and for inflating life rafts. Because it is relatively inert, it is used to provide a nonreactive atmosphere, e.g., for packaging foods, such as coffee, that can be spoiled by oxidation during storage. Solid carbon dioxide, known as dry ice, is used as a refrigerating agent.
There are three principal commercial sources for carbon dioxide. High-purity carbon dioxide is produced from some wells. The gas is obtained as a byproduct of chemical manufacture, as in the fermentation of grain to make alcohol and the burning of limestone to make lime. It is also manufactured directly by burning carbonaceous fuels. For commercial use it is available as a liquid under high pressure in steel cylinders, as a low-temperature liquid at lower pressures, and as the solid dry ice.
What Are Yeast, Anyway?
Yeast are simple fungi. The term “yeast” refers more to a life-style than to a phylogenetic classification. Yeast refers to the unicellular phase of the life cycles of many different fungi, but it is used more commonly as a generic term for fungi that have only a unicellular phase. The organisms most often called “yeast” such as common baking or brewing yeast, are strains of the species Saccharomyces cerevisiae
Dry yeast available in the grocery store is a collection of dormant yeast spores. Once these spores are mixed into water and dough, the culture is active.
Yeast metabolism:
Yeast cells undergo both aerobic and anaerobic respiration. The fermentation of yeast has benefited mankind in the baking and brewing industries.
Use the navigation panel on the left to explore this section on Metabolism.
Question/ Purpose:
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.
The purpose of this project is to study the effect of temperature on production of carbon dioxide via fermentation.
or you can ask:
Does temperature affect the production of carbon dioxide by fermentation?
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.
Independent variable (also known as manipulated variable) is the temperature.
Dependent variable (also known as responding variable) is the rate of CO2 production.
Controlled variable is light (for its possible effect).
Constants are the experiment method, material and procedures.
Hypothesis:
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.
This is a sample hypothesis:
The production of carbon dioxide by fermentation will have the highest rate at warm temperatures. My hypothesis is based on my gathered information about the production of carbon dioxide by respiration? Live organisms will not survive or will have slow metabolism in very low and very high temperatures. Slow metabolism reduces the rate of oxygen consumption and CO2 production.
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.”
Experiment:
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- In a large beaker, weigh 400 grams sugar and add water to bring it to 2 liters. Stir the sugar until it is fully dissolved.
Instead of beaker you may use a 2-liter soda bottle or a bucket. This part is not very sensitive, so if you use 500 grams sugar instead of 400 or if you add more water, nothing will go wrong. - Get 3 identical, clean, 2-liter soda bottles and fill them up to 1/3rd with your sugar solution.
- In each bottle add 1 gram yeast.
- On the top of each bottle place a balloon. Secure the balloon on the neck of the bottle using rubber band or cotton string.
- Label the bottles as cold, room temperature, and warm.
- Place the bottle labeled cold in a bucket of ice. Make sure that crushed ice is surrounding the bottle up to the liquid level.
- Place the bottle labeled “Room Temperature” in a similar bucket without ice.
- Place the bottle labeled “Warm” in a third bucket containing warm water (about 45ºC to 50ºC). You can increase the water temperature by removing part of the water and hot water instead. You may have other methods of keeping the water warm. Consult your supervising adult for safe options.
- Continue your observation and record the size of balloons every hour for 6 hours.
- In a large beaker, weigh 400 grams sugar and add water to bring it to 2 liters. Stir the sugar until it is fully dissolved.
Your data table may look like this:
Balloon volume caused by production of carbon dioxide
| 1 hours | 2 hours | 3 hours | 4 hours | 5 hours | 6 hours | |
| Cold Water | ||||||
| Room temp. | ||||||
| Warm water |
In each hourly observation you must measure and record the diameter of all the three balloons. If your balloons are sphere, you can calculate their volume using this formula:
Volume= 4/3 π r3
In the above formula π is 3.14 and r is the radius of the spherical balloon.
Materials and Equipment:
This is a sample list of materials:
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- 4 2-liter soda bottles
- Yeast (Active dry yeast or moist refrigerated yeast) 10 grams. Yeast can be found in the dairy section or refrigerator section of supermarkets.
- Sugar (about 400 grams)
- 3 spherical balloons. Inflate and deflate the balloons before your experiment so it gets soft.
- Rubber band or cotton string.
- 3 buckets
- Ice
- Hot water.
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.
Calculations:
If you do any calculations for this project, write your calculations in this section of your report.
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.
Conclusion:
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:
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.
References:
Visit your local library and find books related to yeast, fungi, and carbon dioxide. List such books as your references (bibliography). You may also write ScienceProject.com and the following websites as your references.
