Students will develop a straight-line elevation profile of the contour lines of river. This will allow the students to see the river from a two dimensional side profile. This profile will be used to calculate the mechanical energy of the river.
Where is the greatest amount of work done by the river?
What is gravitational potential energy?
What region of the river's elevation profile has the greatest kinetic energy?
What correlations can be made between the river's channel width and potential energy?
Explain the relationship of potential and kinetic energies in the frame of reference of the Law of Conservation of Energy.
Which section of river would you design as a course for rafting based upon the contour lines and elevation profile?
Based upon the data of the elevation profile, which areas of the river are more prone to flooding?
Elevation Profile - Students will create from the elevation contour lines of a topographic map a straight-line elevation profile of the river.
Potential Energy - Students will calculate potential energy of river from elevation profile data.
Elevation profile -Potential Energy Profile - Students will understand the relationship potential energy to the contour of the river
Topographic map - Student will examine the contour lines on map.
Contour Lines
A topographic map with contour lines of the communityor Digital Atlas of your state.
Conservation of Energy
Physics or Physical Science Textbooks to research the equations and units for potential energy, kinetic energy and work.
Graphing equipment
Metric ruler, calculator, paper and pencil
a)Identify the river or stream that you will be locating on the topographic map. b) Follow the path of the river and identify the contour lines that are perpendicular to the river's path and cross the river's path.c)Identify the scale on the contour map to determine what the increment is of each contour line. Use the scale and convert to meters.d)Identify the length of the river over which contour line markings have been identified. Use the length scale of the map to convert the distance to scale in meters.
a) Determine the range of elevation in meters change over the course of the river. This will become the elevation range for the dependent variable(vertical axis) of the elevation profile. Determine an appropiate increment scale for the vertical axis. Label and construct the vertical axis of the elevation profile. b)Determine the length in meters of the river from the first contour line identified to the last contour line identified to construct an elevation profile. This will become the range for the independent variable (horizontal axis) of the elevation profile graph. Determine an appropiate increment scale for the length of the river to label and construct the horizontal axis of the elevation profile. c) Record the distance range and elevation range in meters for each river section between contour lines.d) Construct an elevation profile for each section of river between identified contour line points by plotting the elevation change and correlating distance change on the elevation profile. You will end up with a complete profile of every elevation change plotted on one graph.
a) Record the equations and units for potential energy, kinetic energy and work.b) Calculate the potential energy for each elevation profilesection and record.c) Calculate the work done by the water for each elevation profile and record.
An extension of this activity could be determining the potential energies of locations in the community in which you reside. Make a elevation profile along a route traveled in the city. Determine the slope percent of the hills. Another extension of this activity could be plotting out the best route for a proposed mountain bike trail or ski trail. Use the elevation profile of the route to determine the poetntial energy profile of the trail.
Duration: The duration of the activity will depend upon the length of section of river to be profiled and the nuber of elevation profiles to be constructed. The activity length could vary from 2 class periods to several class periods.
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