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ACTIVITY Proposing Explanations for Fossil Footprints

By Adam Robertson,2014-06-02 23:47
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ACTIVITY Proposing Explanations for Fossil Footprints

    : Proposing Explanations for Fossil Footprints ACTIVITY

    In this activity, students observe and interpret evidence. It encourages students to think “fossil footprint” evidence. From the evidence, critically about the inferences they make and they are asked to construct defensible about the logical relationships between cause hypotheses or explanations for events that took and effect.

    place in the geological past. The estimated time Observations or statements of observations requirement for this activity is two class periods. should have agreement by all individuals: This activity is designed for grades 5 through 8. “These are fossil footprints,” or “The dimensions The activity is adapted with permission from the of one of the footprints is 20 cm by 50 cm.” Earth Science Curriculum Project. Inferences are statements that propose possible Standards-Based Outcomes explanations for observations: “The two sets of

    footprints represent „a fight between the This activity provides all students an opportunity animals.” If this is true, then what evidence could to develop the abilities of scientific inquiry and you look for to support the inference. Note that understanding of the nature of science as the primary emphasis for this activity is described in the rational Science Education developing abilities and understandings for Standards. Specifically, it enables them to: “Science as Inquiry” as described in the ; propose explanations and make predictions Standards.

    based on evidence, Materials and Equipment

    ; recognize and analyze alternative ; Make an overhead transparency of the explanations and predictions, foot-print puzzle from the master provided. ; understand that scientific explanations are ; Have a blank piece of paper on hand to mask subject to change as new evidence becomes the puzzle when it is put on the projector. available.

    Instructional Strategy ; understand that scientific explanations must

    Engage Project position 1 of the footprints from meet certain criteria. First and foremost, they

    the overhead by covering the other two positions must be consistent with experimental and

    with a blank piece of paper. Tell the students that observational evidence about nature, and

    tracks like these are common in parts of New must make accurate predictions, when

    England and in the southwestern United States. appropriate, about systems being studied.

    Point out to the students that they will be They should also be logical, respect the rules

    attempting to reconstruct happenings from the of evidence, be open to criticism, report

    geological past by analyzing a set of fossilized methods and procedures, and make

    tracks. Their problem is similar to that of a knowledge public. Explanations of how the

    detective. They are to form defensible natural world changes based on myths,

    explanations of past events from limited personal beliefs, religious values, mystical

    evidence. As more evidence becomes available, inspiration, superstition, or authority may be

    their hypotheses must be modified or personally useful and socially relevant, but

    abandoned. The only clues are the footprints they are not scientific.

    themselves. Ask the students: Can you tell Science Background for Teachers anything about the size or nature of the This activity provides teachers with the organisms? Were all the tracks made at the opportunity to help students realize the same time? How many animals were involved? differences between observations and Can you reconstruct a series of events inferences. In terms of the Standards, it centers represented by this set of fossil tracks.on the development of explanations based on

    Teaching About Evolution and the Nature of Science, Nat. Acad of Sci, Nat. Acad. Press.

    Have the students discuss each of the questions. that one animal ate the other. Ask students who Accept any reasonable explanations students propose this explanation to indicate the offer. Try consistently to point out the difference evidence. If they could visit the site, what between what they observe and what they infer. evidence would they look for that would support Ask them to suggest evidence that would their explanation? Certain lines of evidence

    support their proposed explanations. the quickened gaits, circular pattern, and

    disappearance of one set of tracks could Explore Reveal the second position of the support the fight explanation. They might, puzzle and allow time for the students to however, support an explanation of a mother consider the new information. Students will see picking up her baby. The description and that the first explanation may need to be temperament of the animals involved are open modified and new ones added. to question. Indeed, we lack the evidence to say Next project the complete puzzle and ask that the tracks were made at the same time. The students to interpret what happened. A key point intermingling shown in the middle section of the for students to recognize is that any reasonable puzzle may be evidence that both tracks were explanation must be based only on those made at one time but it could be only a proposed explanations that still apply when all of coincidence. Perhaps one animal passed by and the puzzle is projected. Any interpretation that is left and then the other arrived.

    consistent with all the evidence is acceptable. Discuss the expected learning outcomes related Should it become necessary to challenge the to scientific inquiry and the nature of science. To students‟ thinking and stimulate the discussion, answer the questions posed by the set of fossil the following questions may help. Students footprints, the students, like scientists, should give evidence or suggest what they constructed reasonable explanations based would look for as evidence to support their solely on their logical interpretation of the proposed explanations. available evidence. They recognized and

    analyzed alternative explanations by weighing ; In what directions did the animals move?

    the evidence and examining the logic to decide ; Did they change their speed and direction? which explanations seemed most reasonable. ; What might have changed the footprint Although there may have been several plausible pattern? explanations, they did not all have equal weight. ; Was the land level or irregular? In a manner similar to the way scientists work. ; Was the soil moist or dry on the day these students should be able to use scientific criteria tracks were made? to find, communicate, and defend the preferred ; In what land of rock were the prints made? explanation.

    ; Were the sediments coarse or fine where the Elaborate You can have more discussions on tracks were made? interpreting series of events using animal prints The environment of the track area also should be students find outdoors and reproduce for the discussed. If dinosaurs made the tracks, the class. Do not forget to look for human footprints. climate probably was warm and humid. If Have students design a different fossil footprint students propose that some sort of obstruction puzzle. Choose several different ones and have prevented the animals from seeing each other, student teams repeat the activity using the same this might suggest vegetation. Or perhaps the learning goals.

    widened pace might suggest a slope. Speculate Evaluate Describe a specific event involving on the condition of the surface at the time the two or more people or animals where footprint footprints were made. What conditions were evidence remains. Ask the students, either in necessary for their preservation? teams or individually, to diagram footprint Explain An imaginative student should be able evidence that could lead to several different, yet to propose several possible explanations. One defensible, explanations regarding what took of the most common is that two animals met and place. They should be able to explain the fought. No real reason exists to assume strengths and weaknesses of each explanation

    using their footprint puzzle.

    Teaching About Evolution and the Nature of Science, Nat. Acad of Sci, Nat. Acad. Press.

    MISSION

    1. Reconstruct happenings from the geological past by analyzing a

    set of fossilized tracks.

    2. Form defensible explanations of past events from limited

    evidence.

    3. As more evidence becomes available, modify or abandon your

    hypotheses.

    I. Questions to Address After Viewing Position #1: A. Can you tell anything about the size or nature of the organisms? B. Were all the tracks made at the same time?

    C. How many animals were involved?

    D. Can you reconstruct a series of events represented by this set of

    fossil tracks?

    Suggest evidence that would support

    your proposed explanations.

    II. After viewing Position #2:

    A. After considering the new information, revisit your first

    explanation.

    B. Modify your explanation and/or add new ones.

Teaching About Evolution and the Nature of Science, Nat. Acad of Sci, Nat. Acad. Press.

    III. After viewing Position #3:

     A. Interpret what happened.

    Remember...Any reasonable explanation must be

    based only on those proposed explanations that still

    apply when all of the puzzle is projected.

    B. Some questions to consider:

    1. In what direction did the animals move? 2. Did they change their speed and direction?

    3. What might have changed the footprint pattern?

    4. Was the land level or irregular?

     5. Was the soil moist or dry on the day these tracks were made? 6. In what kind of rock were the prints made?

7. Were the sediments coarse or fine where the tracks were

    made?

     8. What was the environment of the track area like?

    For each possible explanation proposed,

    be sure to indicate the evidence. If you could

    visit the site, what evidence would you look

    for that would support your explanation?

    Teaching About Evolution and the Nature of Science, Nat. Acad of Sci, Nat. Acad. Press.