Monthly Archives: August 2012

Updated Measurement Uncertainty Activities

Like [last year](, we started Honors Physics with Measurement Uncertainty activities. Based on last year’s experience, last fall’s Illinois Science Education Conference, and this summer’s QuarkNet workshop “[Beyond Human Error](,” we made some minor modifications.

With the popularity of the LHC’s five sigma result, there was more of a context in which to introduce the concept of measurement uncertainty. I mentioned how [calculus and Monte Carlo techniques]( could be used, but we stuck with the Crank-Three-Times method for this algebra-based class.

What was really missing in last year’s activities was how to estimate the measurement uncertainty when performing computer-based experiments. There are so many factors that contribute much more significantly to the measurement uncertainty than the computer-based measurement devices. David Bonner presented on “Learning Physics Through Experiments: Significance of Students’ Interpretation of Error” at the Illinois Science Education Conference last fall. One great idea I took away from his session was a simple and effective approach to addressing this challenge where students perform many trials to establish a range of values from which the measurement uncertainty is determined.

We rewrote the fifth station to introduce students to this method. Rather than using stopwatches, we setup two daisy-chained photo gates connected to a LabQuest 2 to measurement the elapsed time as a cart travels from the first gate to the second. The uncertainty of the LabQuest 2 is insignificant compared to other factors that affect the motion of the cart. Students performed ten trials and determined the measurement uncertainty from the range of values that they measured. We will use this technique throughout the year to estimate the measurement uncertainty.

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Confusion Is Ignorance Leaving the Brain

Someone on Twitter passed along this great quote about students experiencing confusion in physics class:

Confusion is Ignorance Leaving the Brain.

(If you know who, please let me know so I can properly attribute it. **Update**: [@jybuell]( first heard it from Kate Nowak ([@k8nowak](

This quote really resonated with me. I’ve shared it with students who have expressed frustration with feeling confused as they are developing their understanding and refining their preconceptions. I made a note to make some posters featuring this quote, but my lack of design ability kept this task on the back burner. However, while browsing [xkcd]( recently for Computer Science related comics, I found a [couple]( of [comics]( that fit this quote really well. I created a couple of posters that I will put up in class:

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