Summary

In this activity, students will view an animation that explores the importance of including units to communicate the value of measurements effectively. The animation presents definitions, units of measurement, and measuring tools for physical properties that are commonly measured or calculated in chemistry class: mass, length, temperature, volume, amount (moles), and density.

Grade Level

Middle School, High School

Objectives

By the end of this activity, students should be able to:

• Explain why it is always important to include units when recording measurements.
• List the units and tools commonly used for measuring physical properties.

Chemistry Topics

This activity supports students’ understanding of:

• Measurement
• Physical properties

Time

Teacher Preparation: minimal
Lesson: 10-30 minutes

Materials

• Computer and projector with internet access
• https://teachchemistry.org/classroom-resources/units-of-chemistry-animation
• Student handout

Safety

• No specific safety precautions need to be observed for this activity.

Teacher Notes

• All of the animations that make up the AACT Animation collection are designed for teachers to incorporate into their classroom lessons. Intentionally, these animations do not have any spoken explanations so that a teacher can speak while the animation is playing and stop the animation as needed to instruct.
• If you assign this to students outside of class time, you can create a Student Pass that will allow students to view the animation (or any other video or ChemMatters article on the AACT website).
  
• We suggest that a teacher pause this animation at several points, including when questions are posed before the answers are revealed, or watch it more than once to give students the opportunity to make notes, ask questions, and test their understanding of the concepts presented. The student activity sheet can help activate students’ prior knowledge, guide them through the animation, and provide a chance for after-viewing reflection and optional extension questions.
• This animation can be used early in the year to introduce students to common types of measurements they will be making throughout the year (mass, length, temperature, volume, moles, and density), including definitions of these terms, the tools they will use to make the measurements, and the units that are most common in chemistry class.
• The first couple of questions on the student handout ask them to think about measurements in everyday life prior to viewing the animation. This would be a good warmup activity to get the students to activate prior knowledge about measurements. They could use these questions as a think-pair-share prompt to share thoughts with a peer and the class before viewing the animation.
• There is another animation on measurement and converting between units in the AACT library that could be used in conjunction with this one.
• The table of units referenced throughout the animation compares the official SI units to the ones they are most likely to use in a chemistry course. If students are not familiar with SI, you can use some of the AACT resources listed at the end of the teacher notes below, and the National Institute of Standards and Technology (NIST) website also has some great K–12 educational resources about SI, the metric system, and the importance of standards.
• The concept of moles may be a bit advanced for a middle school audience, but the rest of the measurements described in the animation should be appropriate for middle school. If showing this to middle school students, you could just remove the “Amount” line in the table on the student handout and let them know that the concept of moles is something they will learn more about in high school chemistry.
• Students often struggle to understand why they must write their units, since the teacher who is grading their work “knows what the units are.” Hopefully, this animation will allow them to better understand why including units is important to effective science communication. It may help to remind students that they should not makes assumptions about what the person they are communicating with (the teacher, a classmate, another scientist, etc.) knows about their project. They should be recording and analyzing their data so that someone unfamiliar with their project would be able to read their report and understand what they are doing.
• For the final conclusion question, the US Metric Association has a list of “unit mixups,” which range from rather comical (an escaped tortoise), to very expensive (Mars Climate Orbiter crash), to tragic (plane crashes). Even if you don’t use the student handout or ask them to do the conclusion questions, this is a good resource for explaining why it is important to build the habit of always including units.
  • If students want to learn more about Clarence, the Galapagos tortoise and escape artist, there are many articles and videos about his great escape and his life at Moorpark College Zoo, and he even has his own Instagram!
• Classroom resources from the AACT Library that may be used to further teach this topic include:
  • Animation: Measurement
  • Simulation: Measuring Volume
  • Unit Plan: Chemical Measurement Unit Plan
  • Lesson Plan: Setting the Standards of Excellence
  • Lesson Plan: Masters of Measurement
  • Lab: Math and Measurement
  • Activity: Mysteriously Melodramatic & Maniacal Metric Measurements
  • Lab: Significant Figures and Lab Data