View Tube Triangulation
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Pete Insley Jones Metropolitan H. S.
606 S. State St.
Chicago IL 60605
Measuring Distance; Estimating; Averaging; Standard deviation
Meter sticks, rulers, cut down paper towel cardboard tubes
First, get the students to estimate the height of the chalkboard or the
doorway. List the estimates and use a calculator to find the average and
Stand far enough away so that you can see the entire object in the tube.
Use a proportion to find the height of the object.
Height of object = Distance of tube
Distance to object Length of tube
List the calculations and again find the average and the standard
deviation. Take some time to discuss what they mean again.
Now get a couple of students to measure exactly how big the object is.
Have a prize for the best estimate of measurement.
Collect paper with original estimate and calculation of height. Have
students write a short paragraph stating how well they think they did on the
You can find percentage error in this lab and it has some new meanings to
the students. Have them find their % of error. You can also find the probable
percentage of error from the standard deviation.