Sidewalk trackways
It
is surprising just how many "fossil" trackways are in every community. Dogs,
cats, birds, and even people often make a leave trackways excellent trackways in
cement. If you look around your school and neighborhood you will most likely
find a few trackways left in cement. I often find trackways left by birds and
pets that were made while the sidewalk cement was still wet.
To get some dinosaur tracking practice, start by taking a walk around the
school or in your neighborhood and try to find some of these cement trackways.
Once you find one you can use that section of the sidewalk trackway to calculate
the speed of the animal as it walked across the wet cement. To do this activity
you will need a measuring tape, some sidewalk chalk, and a notebook to record
your measurement. If you have one, a digital camera can also be a great tool.
In the picture to the left, while skating, I found a trackway made by a duck
as it walked across the sidewalk on the way to a pond. The picture on the
right was made by a smaller bird (notice the dime that was used for scale).
1. |
When you have found a trackway, start by measuring the foot
length. Sometimes you don't have a really clear print, so it is necessary to
measure a few of the prints and take an average. Use the formula F*4 (foot
length times four) to calculate the hip height of the animal. |
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2. |
Use some chalk to outline the trackway and to mark your
measurement. Pick a spot on the foot that you can use, such as the back,
front toe, or center and mark that on each of the prints. Also, number each
of the prints, starting from the back and moving forward. Now draw a rough
diagram of the trackway in your notebook. |
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3. |
Now measure the stride length for each set of prints.
Remember that the stride length is the distance from one right footprint to
the next right footprint, or the distance from one left footprint to the
next left foot print. Record your measurement in your notebook. |
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4. |
Use your notebook to create a table of the data, and then
calculate the speed during each stride. |
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