"Are your measurements accurate?" "How precise is that measurement?" Students oftentimes mistakenly believe that these two questions are asking the same thing. In this lesson, students will perform several hands-on activities and view short video clips in order to help them differentiate between accuracy and precision. They will first be introduced to the topics with a short series of hands-on activities. The entire lesson relies heavily on biotechnology equipment such as the micropipette, access to the Internet and devices for students.
Students will be able to:
1. Demonstrate strategic computation, pipetting, reasoning skills needed to accurately complete the calculations they will encounter in future lab investigations such as when creating cell culture media and antimicrobial compounds.
2. Define accuracy and precision, and differentiate between the two terms.
3. Apply the concepts of accuracy and precision to the preparation of biotechnology products as well as data analysis and quality control.
National Biotechnology Standards:
BT.1.8 Demonstrate the ability to follow Standard Operating Procedures (SOP).
BT.12.1 Trace the source on any large disparity between estimated and calculated answers to problems.
BT.12.3 Recognize the relationship between accuracy and precision.
Engage (Activate Student Thinking)
1. Display the following slide and invite students to respond to the following inquiry:
Would you rather...have a pilot that is accurate in flight landings or have a pilot that is precise in flight landings? Justify your answer.
2. View the following video (Time: 3:17min) located on YouTube. Students should collect evidence from the video to either support or refute the preference they stated in Question #1.
3. Students should share their preference as well as their justification during a whole group share session. Finally, have students predict a response to the following inquiry as a transition to this next portion of this lesson:
Explain the difference between accuracy and precision in terms of collecting data and taking measurements.
Explore (Guided/Student-Centered Activity)
How can we determine the effects of measurement and computation errors in the biotech lab ?
Students should complete the online training course of their choice, Determining Glassware Accuracy or Pipetting in preparation for the hands-on component of this lesson. If time permits have students complete both lessons and obtain certification in each area in which accuracy and precision are key components. Both lessons introduce the use of the mathematical analysis tools standard deviation and percent error as ways to detect if there are errors in our measurements, data, and/or computations as well as place them in a virtual environment that enables them to evaluate the effects of errors.
Explain (Formulate Ideas)
Preview the questions below with students and then view this video (Time: 3:15min) located on YouTube and then either using a Quikwrite, Turn and Talk or other reflection or share out strategy have students respond to the following inquiries:
1. What does standard deviation tell us about the data we have collected?
2. Why is standard deviation useful to our work in the biotechnology workplace?
Elaborate (Apply and Extend Understanding)
Students will create a work of Art of based on accuracy & precision when using a micropipette through this unique performance assessment.
Evaluate (Monitor Understanding)
Distribute one Velcro dart game to each group of 3 to 4 students, along with a copy of the handout "Bombs Away" for each student. I got mine from Lakeshore Learning store. Have the groups complete the activity as outlined on the handout, and record their results.
Discuss the results and ask, "How accurate and precise were your bombing runs? What do we mean by accuracy and precision?" Student should have a greater than basic understanding and now a personal connection to what scientists consider accuracy and precision to be after completing the hands-on activities as outlined in the Elaborate and Evaluate sections of this lesson. Students will analyze their groups data and results using the following analysis questions as a guide.