Introduction: Go Green by Growing Green: How to Extract Energy From Grass
Mowing the lawn is hard work, especially on a warm day. Not only do you have to mow the grass, but you also have to dispose of the clippings. Some people add the clippings to a compost pile in their yard, which is a great idea. But did you know that some grasses can be used as a source of energy?
To grow three different types of grasses and then determine which grass produces the most biomass and therefore, will produce the most energy. C
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Step 1: Materials and Equipment
A project kit containing most of the items needed for this science project is available for puchase from AquaPhoenix Education. Alternatively, you can gather the materials yourself using this shopping list:
3.Potting soil (1 bag)
4.Hand trowel; available at your local garden centre
7.Wheat or rye seeds (90); can be purchased from your local health food store
8.Corn seeds (90); available at your local garden centre
9.Oat seeds (90), whole and not milled; available from your local health food store
10.Watering can, small or a cup or any other container you can put water in
11.Optional: Container to hold excess water from the plants (1–3, depending on how many trials you are running; see the Experimental Procedure for details)
12.Bucket or large waterproof container for rinsing plants
13.Paper towels (1 roll)Plastic baggies, sandwich size (1 box)
14.Flowerpots with drainage holes (9) at least 3.5-inch wide or make your own pots from cleaned ½-gallon paper milk or juice cartonsIf you are making your own pots from cartons you will also need a Philips head screwdriver, ¼ inch and a pair of scissors
15.Plastic baggies, sandwich size (1 box)
16.Digital scale with high resolution, such as the Fast Weigh MS-500-BLK Digital Pocket Scale, 500 by 0.1 G, available from Amazon.com.
a)The scale should be able to reliably measure changes as small as 1 gram (g) and 0.1 ounce (oz.).
b)If you don't have a digital scale in your kitchen, you could ask to borrow one from your school, or purchase one from your local home goods store.
c)As an alternative, you could also borrow a triple-beam balance from your school.
17.Optional: Grow lamp, if you are doing this science fair project without several days of warm and sunny weather; can be purchased online from websites such as www.amazon.com
Step 2: Procedure
If you have bought pots with drainage holes, skip to step 2. If you are making your own pots from cartons you will need to prepare them as follows:Make sure your cartons have been well cleaned.Use a ruler and pen to measure and mark the cartons half way up their height.Use the scissors and carefully cut all of the cartons in half at the mark you measured.Discard the upper halves of all of the cartons. You should now have nine paper plant pots. Make sure that all of the pots are the same height.Place a towel on a hard surface, like a table top, then place the first pot on top of it, with the open end up. Use the Philips head screwdriver and carefully poke six drainage holes in the bottom of the carton. These holes will allow excess water to drain out. Repeat this step with all of the cartons, using a towel underneath each one to protect the surface underneath.Now fill three of the pots with potting soil, using the hand trowel. Fill the pot at least half way with soil. You can fill it as much as1 centimeter (cm) from the top. Lightly pack the soil into the pot with your hand.Label the three containers, using masking tape and a pen, as follows;Pot 1: Trial 1: Wheat (or Rye)Pot 2: Trial 1: CornPot 3: Trial 1: OatsTake 30 wheat or rye seeds and plant them in the first pot that is labeled Wheat or Rye. You should plant the seeds in an orderly fashion. For example, you should plant five rows of six seeds each, with the seeds evenly spaced. Gently push each seed 1/2 inch into the soil. Cover the seeds with soil, and put a little more soil on top, filling the container all the way to the top.Repeat step 4, planting 30 corn seeds in the Corn pot.Repeat step 4, planting 30 oats seeds in the Oats pot.Check the seed packet to determine the temperature range for each plant.If you are doing this science fair project while it is still warm and sunny outside on most days:You can place the plants outdoors.You can then run two additional trials at the same time. The purpose of performing more than one trial is to minimize error and uncertainty in your data.Repeat steps 3–6 two additional times, labeling the pots with trial numbers 2 and 3. Place each set of three pots, one of each seed type, at three different sunny and warm locations in your yard.If it is too cold outside:You should use a grow lamp to provide light to your plants.The top of the plants should be 7 1/2 –10 centimeters (cm) from the grow lamp.If you are using a grow lamp as the source of light, then you will have to wait until the first trial is completed before starting the second trial, and then wait for the second trial to complete before starting the third trial.Carefully water each pot of seeds with the watering can. You should water the pots with enough water that they start to drip from the drainage holes.If the plants are inside you may want to use a container underneath the pots to catch the extra water that drips out of the drainage holes.Note down in your lab notebook the date that you planted the seeds in a data table, like the one shown below.
Observe your pots daily, and keep the soil moist. As soon as you see the first seedling, mark down the seed type and the date in the data table. Continue observing each day and record when you see the 10th and the 20th seedling for each seed type.Start measuring the height of the seedlings two days after the first sprout comes up. Record the height and type of each seedling in another data table, like the one shown below. You should have nine height data tables, one for each seed type for each trial. Then calculate and record only the average, by day, in your Plant Growth and Development data table.
Fourteen days after seeing the first sprout (not of each type, but the first one among all of the plants), weigh the wheat or rye seedlings, the corn seedlings, and the oat seedlings, as follows:First fill a bucket with water and then gently wash the soil off the leaves and roots. Try to get rid of as much dirt from the roots as you can. This will take time so be patient. See Figures 1 and 2, below. Note: Don't clean all of the plants from the different seed types together. Just clean one group of plants at a time.Once a group of plants is clean, dry it completely with paper towels and then temporarily store the group of plants in a plastic baggie. Label the plastic baggie with the seed type and trial number. If you have been growing the seeds outdoors, you will have nine baggies: three with wheat or rye seedlings, three with corn seedlings, and three with oat seedlings. If you used a grow lamp, you will only have three baggies right now, one for each seed type.
Now place a new paper towel on the digital scale. Open the first wheat or rye baggie and weigh the group of seedlings. This is the "fresh weight." Record the fresh weight of the seedlings in a data table, like the one shown below.
If you used a grow lamp to provide light for the plants, repeat steps 3–17 two more times. The purpose of performing more than one trial is to minimize error and uncertainty in your data. Record all your data in your lab notebook.
Plant Growth and Development
Trial Germination Average Height
Plant Planted Date Date of 1st Date of 10Th Date of 20th 2 4 6 8 10 12 14
Sprout Sprout Sprout. Days Days Days Days Days Days Days
Wheat or Rye
Day Seedling Heights Average Seedling Heights
Seed Type Trial Fresh Weight Dry Weight Percent changes
Wheat or Rye
Equation for making a bar graph
Percent Change in Weight = Fresh Weight - Dry Weight
Fresh Weight × 100
Analyzing the Data
Now you can analyze and graph your data. You can make your graphs by hand or if you want to learn more about graphing or make your graphs online, try the following website: Create a Graph.Graph the average height of each seed type versus time. Label the x-axis Days and the y-axis Height.Make another graph, plotting the fresh weight and the dry weight for each of the seed types that you used. Label the x-axis Seed Type and the y-axisWeight.You can also plot the percent change in weight between fresh and dry for each seed type. Label the x-axis Seed Type and the y-axis Percent Change in Weight. Looking through the data, can you determine which of the seeds you chose yields the most biomass and would be the best converter of light energy to biomass energy?
The data is to be made from the charts