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wks1 [2019/08/13 16:47] (current)
rachel created
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 +===== Uncertainty in Measurement =====
 +
 +There is little that can be scientifically investigated without taking
 +measurements. By taking and analyzing data, we can develop models that
 +inform us of how the world works. However, to be able to analyze data
 +effectively,​ critical decisions need to be made regarding how the data
 +are being taken in order to determine its validity.
 +
 +This uncertainty is not a fault of experimental science, and does not
 +give credence to "​theory being more perfect than experiment."​ The idea
 +of uncertainty is found in every aspect of science -- in experiment we
 +call it *error* or *uncertainty*,​ in theory we are limited by the
 +*assumptions* made, and in engineering we define our products to be
 +within a *tolerance.* In all instances, these forms of uncertainty
 +describe how *confident* the scientist is in their measurement -- it
 +defines the range of values within which they are *sure* the reported
 +value falls.
 +
 +Defining uncertainty is a skill that is developed over time and, like
 +any other skill, takes practice. As it is a major tool used in nearly
 +every aspect of science, it has become a major learning goal of DATA
 +Lab, both this semester and next (should you take PHY 252).
 +
 +In this workshop, you are tasked with taking a series of measurements.
 +Your data will be pooled with the rest of the class -- affording us a
 +backdrop against which to discuss measurements and uncertainty. The
 +discussions with the larger group will help inform your decisions in
 +experiments as well as help you develop a deeper understanding of what
 +uncertainty means and how it is used in science. Afterwards, you and
 +your group will be presented with a final measurement that you will
 +record and assign uncertainty to. By using the information in class, you
 +will justify your experimental decisions and value reported.
 +
 +==== Research Concepts ====
 +
 +In order to be productive in class, it would be helpful to research
 +before class:
 +  * What reported data means
 +  * Why uncertainty is assigned to measured data
 +  * How the assigned uncertainty reflects the confidence of the reported value
 +  * The difference between random and systematic uncertainty
 +  * How to calculate the mean of data set
 +
 +==== Measurements and Uncertainty ====
 +
 +**Part 1 -- Measurements**
 +
 +There are five measurements you are tasked with taking: the length of a
 +metal block, the diameter of a bouncy ball, the length of a string, the
 +mass of a weight, and the angle of a board. After you take these
 +measurements,​ record the values you obtained on the white boards
 +provided. It may be helpful to consider and document in your notebook
 +  * How was each measurement taken?
 +  * Were there any complications that arose while taking your measurements?​
 +  * Did the way you took your measurement affect the value you obtained?
 +
 +**Part 2 -- Discussion of Uncertainty**
 +
 +Scientists will include values of uncertainty when they report data.
 +Your group will be assigned one of the sets of measurement data to
 +discuss. In this discussion, consider:
 +  * What do the reported values mean?
 +  * How difficult was the measurement to make? Why?
 +  * What does the amount of variability tell you about the uncertainty in the measurement?​
 +  * Are there other things the variations tell you?
 +  * Can you assign a quantitative value for the uncertainty of this set of data?
 +
 +You will then report your group'​s discussion to the class.
 +
 +**Part 3 -- Obtaining and Reporting Data**
 +
 +Your group will be tasked with taking one additional measurement. The
 +experimental decisions your group makes will affect the value and
 +uncertainty of your measurement. Document these decisions and determine
 +a value for the measurement and its uncertainty. Justify your values
 +based on the decisions you made and the discussions held in class.
 +
 +At the end of the day, you will each turn in your notebook. While your
 +entire entry will be evaluated, in order to narrow our scope feedback
 +and assessment will primarily focus on what you submit for **Part 3**,
 +especially
 +  * The value reported and the uncertainty assigned.
 +  * How you documented your measurement and the experimental decisions you made.
 +  * Justification for your assigned value and uncertainty and how it related to the discussions held in class.
  
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  • Last modified: 2019/08/13 16:47
  • by rachel