Burning Biofuels: Comparing Nonrenewable and Renewable Fuels
AbstractHave you considered where the gasoline that your parents put in your car comes from and how long that source will last? The fuel that most vehicles use, gasoline, is a petroleum product. Petroleum is a fossil fuel and is a nonrenewable form of energy, meaning we use it faster than it is able to be reproduced. Burning fossil fuels also produces pollutants that might hurt our environment. Using a kind of fuel from a renewable source would help save Earth's natural resources and cut down on pollutants. In this science fair project, you will investigate whether a renewable fuel produces the same level of energy as an equivalent amount of nonrenewable fuel.
Michelle Maranowski, PhD, Science Buddies
This science fair project is based on an experiment written by the National Renewable Energy Laboratory (NREL):
- National Renewable Energy Laboratories Education Programs. (n.d.). R.E.A.C.T. Renewable Energy Activities—Choices for Tomorrow. Retrieved March 4, 2009.
To determine if the energy in a biofuel is equivalent to the energy in the same amount of nonrenewable fuel.
There's a lot of talk nowadays about renewable and nonrenewable energy sources. But what do those mean? Renewable energy is energy that is extracted from sources that are naturally replenished; such as the wind, water, and Sun. Nonrenewable energy comes from fossil fuels. Fossil fuels are made from the bodies of animals and plants that lived millions of years ago and were exposed to heat and pressure in the Earth's crust for millions of years. Coal is one example of a fossil fuel. It is a limited resource, and extracting energy from coal creates by-products that are believed to damage the environment and contribute to climate change.
Biofuel is a form of renewable energy. Biofuel (bios means life, in Greek) refers to living and recently dead biological material that can be used as solid, liquid, or gaseous fuel. Agrofuel (agro usually refers to agriculture or crops) is a type of biofuel and is also a form of renewable energy. Agrofuel is produced from specific crops. There are two ways to grow agrofuels. The first is to grow crops that are high in sugar, such as sugarcane or sugar beet, or that are high in starch, such as corn. Then use fermentation to produce ethanol. Engines can be modified to use ethanol fuel instead of gasoline. The second strategy is to grow crops that have high oil content, such as soybeans. When heated, the consistency of the oil changes into a form that can be used directly in diesel engines.
There are disadvantages, however, to using agrofuels. Agrofuels compete for land and resources with other crops that are grown solely for food. Clearing land for growing agrofuels threatens biodiversity and drains the local water supply. Instead of growing crops specifically for agrofuels, it might be a better option to convert waste vegetable oil into fuel. This is a complicated, but doable, process.
The first step in using agrofuels is to figure out if it's as good an energy source as nonrenewable fuel. In this energy science fair project, you will determine if equivalent amounts of a renewable agrofuel release the same amount of heat energy as a nonrenewable fuel. You will use fresh vegetable oil as the agrofuel and motor oil as the nonrenewable fuel to heat water. Will the peak temperature depend on the type of fuel used? Get to work and find out!
Terms and Concepts
- Renewable energy
- Nonrenewable energy
- Fossil fuel
- Absolute value
- What are some sources of biofuel?
- What are some sources of agrofuel?
- What are the disadvantages to harvesting energy from agrofuels?
- Wikipedia Contributors. (2013, April 8). Biofuel. Wikipedia: The Free Encyclopedia. Retrieved April 11, 2013.
- National Renewable Energy Laboratory (NREL). (2008, July 25). Learning About Renewable Energy: Biofuels. Retrieved March 4, 2009.
- NOVA. (2011, April 20). Power Surge. Retreaved April 11, 2013.
For help creating graphs, try this website:
- National Center for Education Statistics. (n.d.). Create a Graph. Retrieved November 12, 2008.
Materials and Equipment
- Paperclips, large (2). The paperclips must be metal and not coated with plastic.
- Cotton cordage 1/2-inch (in.) diameter, 1-foot (ft.) length; available at fabric stores or craft stores
- Soda can, 12-ounce (oz.), cleaned and metal tab removed
- Liquid measuring cup, metric
- StyrofoamTM cup
- Scientific thermometer; available at science stores or online from Amazon.com
- Ring stand; available at science stores or online from Amazon.com
- Ring clamp; attaches to ring stand, ring should be approximately 3 inches in diameter. Available at science stores or online from Amazon.com
- Medicine dropper or disposable pipet; pipets can be purchased online from Amazon.com
- Motor oil, #20 or #30; available from your local auto supply store
- Vegetable oil
- Optional: Aluminum foil
- Fireplace or grill lighter
- Baking soda (1 box)
- Paper towels, moistened
- Lab notebook
- Graph paper
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- Unfold a paperclip to make a holder. It should look like a letter "Z" with a tail on the end. See Figure 1.
Figure 1. Paperclip holder
- Measure and cut a 1 1/2-in. piece of cotton cordage. Poke one end of the paperclip, lengthwise, through the cotton. See Figure 2.
Figure 2. Paperclip holder with the piece of cotton cordage on the end.
- Measure 100 milliliters (mL) of water in the liquid measuring cup and pour it into the empty and clean soda can.
- Place the open end of the Styrofoam cup over the top of the soda can. Poke a hole the same diameter as the thermometer in the top of the cup over the opening in the soda can. Insert the thermometer through the Styrofoam cup and into the soda can. The thermometer should sit in the water, but should not touch the sides of the can. Most lab thermometers come with a plastic fitting that slides over the body of the thermometer. Use this plastic fitting to keep the thermometer from sliding and touching the side of the can.
- Now set up the ring stand. Set the ring stand in a well-ventilated area and on a non-flammable surface. There will be small flames and smoke produced during the following steps. Make sure that there are no flammable or combustible items nearby. Slide the smallest ring onto the stand's post; do not tighten it yet.
- Suck some vegetable oil into the dropper. Squeeze 35 drops onto the cotton cording on the paperclip. Take your time and make sure that all of the oil soaks into the cotton.
- Place the moistened cotton and paperclip on the base of the ring stand, directly under the ring. The cotton should be 2 in. from the plane of the ring and positioned so it is vertical to the ring stand base. Tighten the ring to the post. See Figure 3.
A thermometer reads the temperature of a can filled with water. A piece of cotton soaked in oil is lit underneath the can and the thermometer is used to measure the temperature changes of the water.
Figure 3. This image depicts the experimental setup.
- Place the soda can and thermometer contraption so it is resting on top of the ring. If the soda can falls through the ring, wrap some aluminum foil around the ring to reduce its diameter. Make sure that the can sits securely on the ring.
- Take a thermometer reading of the initial temperature of the water. Note this reading in your lab notebook in a data table, like the one shown below.
|Oil||Trial||Initial Water Temperature||Final Water Temperature||Percentage Change||Start Time||End Time||Time that the Cotton Stayed Lit||Observations|
Now light the cotton using the fireplace lighter. Caution: Have an adult help you perform this step. Make sure to have an open box of baking soda nearby. Baking soda can extinguish grease fires safely if you completely cover the grease fire with the baking soda.
- Make sure that you get a flame going. This may require that you light the cotton from a couple of different sides.
- Observe how easy or difficult it was to light the cotton. Note this observation in your data table.
- Start the stopwatch when the cotton lights. Caution: Keep away from the smoke, as it can have an unpleasant and irritating odor.
- Stop the stopwatch when the flame goes out. Read the temperature on the thermometer. Watch it for a few minutes to make sure that it doesn't change. Once the temperature stops changing, record the value in your lab notebook.
- Gently blow out the glowing, hot cotton. Don't blow too hard or the ash will blow all over and make a mess. Use some moistened paper towels to clean up the ash and the residual cotton from the paperclip. Carefully remove the thermometer from the can. Pour the water from the can into the sink. Rinse off the outside of the can. Be careful, because the soot on the outside of the stand can stain your hands and clothes. Clean everything with the paper towels. Open nearby windows to drive any remaining smoke out of the room. Using a fan will help.
- Repeat step 2 and steps 6–13, using vegetable oil, two additional times. Refill the can each time with fresh, cool water. The water should be approximately the same starting temperature (give or take 2 degrees) each time. Record all data in the data table in your lab notebook.
- Repeat step 2 and steps 6–13, using motor oil, three times. Refill the can each time with fresh, cool water. The water should be approximately the same starting temperature (give or take 2 degrees) each time. Caution: The motor oil smoke can be especially unpleasant and irritating, so make sure you stay away from the path of the smoke. Record all data in your lab notebook.
- Analyze your data. Calculate the percent change between the initial water temperature and the final water temperature. Equation 1 shows how to calculate the percent change between the initial temperature and the final temperature.
|Percent change =||(final water temperature - initial water temperature)
initial water temperature
- Graph your data on a scatter plot. If you would like to learn more about graphing, or would like to make your plots online, try this website: https://nces.ed.gov/nceskids/CreateAGraph/default.aspx. Label the x-axis Oil Type and the y-axis Final Temperature. Make a second scatter plot. Label the x-axis Oil Type and the y-axis Percentage Change in Temperature. On both of your plots, note your observations. Which oil was easier to light? Which flame lasted longer?
Ask an Expert
- Repeat the science fair project with different types of oils. For example, try safflower oil or olive oil.
- What are the characteristics of each type of oil? How do they compare? Does this account for any of your observations?
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