Lab Exercise
Remember that field labs must be done in order....on time if possible.
Review the principles of designing a good experiment. An experiment should test a hypothesis or prediction about the behavior of specific objects by gathering data on what happens to identified and measurable characteristics (dependent variables) of the objects when conditions affecting them (independent variables) are varied in a controlled way. If possible, conditions are controlled so that only one independent variable is manipulated at a time. The experimental procedure is replicated, either by running the experiment repeatedly or by running it several times simultaneously under the same conditions. The results are then compared to the predictions.
You will need to find an outdoor area at least 20 x 20 feet, which you can have access to at most times of the day for most of the year. It should have a wide variety of plant and animal life. The ideal area for this kind of observation is one which is still natural and open to different kinds of animals. A nature trail or greenbelt, undeveloped area of a park, farm field, or meadow are all good choices and will provide a variety of plants and animals to observe. Your backyard or local park are also possibilities, although they may not contain as many different types of organisms as an open area.
After you have identified the area, begin to inventory all plants and animals that you see. Keep your observations in a spiral or loose leaf notebook you can take with you into the field.
Prepare a summary of your observations in a format that you can use for subsequent observations. This will make comparisons easier. Remember that the goal of any scientific report should be to include enough information that a similarly-equipped peer can duplicate your observations and check his own results against yours. You may want to review mycroft's report below before writing your own.
Turn in a report similar to mycroft's. It should include the date, time, weather conditions, and temperature; a description of the area, general observations, and a table with the organisms observed and their identification.
mycroft's report
Field notebook entry August 7, 2000. Late afternoon and early evening 5pm-6:30pm PDT.
Weather is sunny and dry, approx. 70 deg F.
Location: Jogging trail along 161st Avenue SE, Bellevue, between 28th Place and Eastgate Way. Trail area is 50-70 feet wide by one mile long with less than 20 foot change in elevation; most of trail is between street and parking area, so animals are disturbed by passing traffic.
General notes: Plants are native to area but not entirely wild, since the trail is maintained by city and corporate groundskeepers. Plants range from primarily conifers at northern end through mixed forest to primarily deciduous at southern end.
Organisms observed:
Tree: dark grey-green needles, stiff, 1/2" long distributed evenly around stem. Limbs primarily horizontal near bottom of tree, rising upward near top. Bark grey with ridges. Tree height 50-60 feet.
Noble fir
4
Tree missing limbs on lower south side, possible due to lack of sunlight.
Tree: dark green needles, tips of branches with lighter green needles 1/2" long, distributed evenly around stem. Bark smoother than noble fir.
Douglas fir
2
Tree has many broken branches.
Tree: Maple-shaped leaves over 10" across; many stems or trunks
Vine Maple
6
Growing on street side, gets direct sun at least 1/2 day
Tree: Maple-shaped leaves mostly 8" or less across; many stems or trunks
Vine Maple
1
Growing under cedar in shade
Snake: approx. 3 feet long, black with green stripes
Garter snake
1
Coiled in the sun
Bird: black with redwings
Redwing blackbird
1
In cedar tree
Hypothesis for further study: Vine maples grow better in direct sunlight than in shade.
Dependent variable: Number and size of leaves on plant; length of time on plant (when do they drop off in the fall?); date of appearance in the spring.
Independent variables: Amount of sunlight. Note: soil type is likely to be more acidic under conifers; elevation and drainage may contribute to differences in water available. Observed trees should be close together.
Control group: No specific control group can be determined. A range would help in establishing the tendency (trees in full, partial, and no sunlight).
Replication: Two vine maples in each type of location (full, partial, no sun) will be selected. Differences in drainage will be noted.
Expectation: Vine maples receiving direct sun will be larger, have larger leaves in greater numbers, develop their leaves sooner and lose their leaves later, than those growing in shade
Measurements should be added at this point, and conclusions....but that should be enough to give you an idea of the information to collect.
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