Biofuels
Biofuels (Athena Meltzer)
Author(s)
Athena Meltzer, Richard E. Byrd Middle School
*I have not yet done this with my students but I will be starting this with my class the second week in January as by then we will have covered the prerequisites (photosynthesis, cellular respiration, fermentation, carbon cycle, and why the use of fossil fuels is harmful to the environment.
NGSS Engineering Standards
Instructional Resources/Background Information
Environmental engineers design products and processes that are friendly to the Earth. In this lab we investigate ways to provide energy without using environmentally harmful fossil fuels.
Brainstorm with students possible alternative energy sources (Possible answers: solar, wind, hydropower, nuclear, or biomass.)
Focus students on solar power.
Some engineers have worked on creating cars or homes that use solar panels that generate electricity.
Ask students to brainstorm other ideas for using sun's energy to power a car
Biofuels are a natural way of storing the sun's energy, and we can put it into the car just like gasoline.
Biofuels are a renewable form of fuel that biochemical engineers have created from biological material such as plants.
Engineers figured out a way to turn the starch and sugar of corn and other plants into fuel called ethanol.
With current technology, ethanol can only be efficiently made from the edible part of corn.
Biochemical engineers are currently trying to find a way that we can also use the nonedible parts, such as the husks, which much first be converted into starches before they can be used
This would be a resourceful & inexpensive way to use all of the biomass that is left over after the corn is harvested.
Idea behind biofuels
Instead of converting the sun’s energy into electricity directly, like solar cells, plants convert the sun’s energy into sugars and starches – the food they need. The plant does this through a process called photosynthesis. The chlorophyll in the plant’s leaves uses the sun's energy to turn carbon dioxide and water into glucose and oxygen. Later, in a biorefinery, the glucose is combined with an enzyme found in yeast so that it can be turned into ethanol, which provides the chemical energy that can be used to power cars.
Sugar + Enzyme Found in Yeast = Ethanol + Carbon Dioxide
Many different kinds of engineers work together to create alternative energies, such as the biofuel called ethanol.
Biochemical engineers work out the process for converting corn and other plants into ethanol.
Bioengineers alter the genetic make-up of the plants themselves to make them more effective as raw materials for the biorefinery process.
Mechanical engineers design the machines that harvest the plants and transform them into ethanol.
Civil engineers may use plants to act as purifying agents in biological water treatment processes.
Many treatment facilities rely on artificial or natural lagoons of plants and fauna for the removal of contaminants before release into the environment.
Environmental engineers are developing ways to seed the ocean with algae.
Photosynthesis from the algae removes CO2 from the atmosphere, as a way to combat global warming. (Algae can be used to produce biofuel as well.)
While biofuels might be less harmful than fossil fuels, they do have some downsides.
To grow corn to produce ethanol, farmers must use potentially harmful fertilizers,as well as fossil fuels to power equipment like tractors.
Using items like corn for fuel instead of food could lead to food security issues,
due to both the amount of food available and rising prices for food when the amount of that food decreases.
Similarly, the land used to grow biomass for biofuels might be needed for other things like food production.
While corn is currently a highly publicized source of biofuel, other plants such as switchgrass or even grass clippings, might be more environmentally friendly.
Switchgrass is not used as food and requires little fertilizer,while at the same time containing enough sugar to make it a viable source of fuel.
Ethanol production causes CO2 to be released, the CO2 will be absorbed by the next crop of plants. This cycle prevents CO2 from becoming a problem.
PROBLEM
Humans continue to use harmful fossil fuels as the primary fuel for vehicles and industry
With current technology, ethanol can only be efficiently made from the edible part of corn.
Determine factors that should be considered when selecting a type of biomass for biofuel production.
DESIGN
design an experiment to compare the amount of ethanol produced by the fermentation of various organic materials such as corn, grass, and fruits.
research the pros and cons of growing and processing these materials for use as biofuels
Extension: use the information from their experiment and research to design a biorefinery plant.
GOALS OF LESSON
To introduce students to the reasons for biofuels
To encourage students to investigate what kind of biomass might be efficient sources of biofuel
Materials needed
Corn kernels
Table sugar
Soybeans
Fruit
Potato
Corn husks
20 oz. soda bottles
Yeast
Hydrometer
Calculators
Balloons
Scale
Weigh boats
Gloves
Small scoops
Mortar and Pestle
string
ruler
marker
Rubric for Grading
Procedure
Have students form POGIL groups of 4 students
Each group selects 3 types of biomass to test
For each type of biomass, prepare a different soda bottle. Students must also have a control bottle. They will label the bottle with the biomass they will be placing inside. For example, bottle 1 could be labeled «corn», bottle 2 «sugar, bottle 3 «grass», etc
Using the weigh boats and scales, measure and place 2 grams of yeast into each of the bottles they are preparing.
Break up the biomass you are using. For example, they should grind corn or mash up fruit using the mortar and pestle. (you can provide materials that are already ground up such as corn meal or table sugar)
Measure each type of ground up biomass to ensure that the same amount of biomass is being placed into the bottles. 10-20 grams of each material is sufficient.
Once the dry materials are placed inside the bottle, fill a balloon with warm, not hot water, just until the balloon starts to expand slightly.
Place the balloon on the top of the soda bottle such that the warm water goes into the bottle and the balloon forms a seal around the top of the bottle. Repeat for each of the bottles.
Once all bottles have warm water and balloons, gently agitate the bottles to mix the ingredients and place bottles in a warm place.
It may take several days for fermentation to occur.
Make and record observations daily. Is the balloon expanding? How much? Do you notice bubbles?
While waiting for fermentation to occur, research how each of the materials you selected are turned into biofuels. How are they grown? How much land is required? What types of fertilizers, etc. are needed? What type of processing must occur? Is this type of biomass needed for food?
After a week, make their final observations and record the expansion of each of the balloons (using the string and a ruler). Carbon dioxide is a product of the fermentation reaction, and this gas, not ethanol, is what causes the balloon to expand. By measuring the expansion of the balloon, you can get a comparative sense of how much ethanol is being produced by the breakdown of each biomass. (Note that before ethanol can be used as a biofuel, it must be distilled from the mix.)
Once measurements have been taken, compare the ethanol production of each of the materials your group tested. Using this data, as well as the research you conducted, work together to design a biorefinery plant.
First determine which biomass they would use to make biofuels. Things to consider: ease/cost of production;amount of fossil fuels needed from production;efficiency of ethanol production; removal of food away from people who need it, etc.
Think about where the biorefinery plant will be located, how much space they will need be needed, is there any special equipment that might be required?
Your group will present and defend your decision in front of the class. Presentations could include drawings or blueprints of the design, photo slideshows, etc.
Questions
Photos
Movies
Because I have not yet done this with my students I do not have video of them working. However, here is a video I would start the unit with
I just found this video very inspiring
This video gives students an idea of how plants contain chemicals that could be used for biofuels