Exploding Popcorn: Exploring How Internal Temperature Affects Mass and Volume (Part 2/2)

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SWBAT measure changes in mass and volume of a popcorn kernel.

Big Idea

Matter is all around us and is always changing. By investigating how popcorn changes when it is popped, students learn about mass and volume.


The Exploding Popcorn Lab is a guided inquiry investigation including lessons taught over the span of 2 -3 days. To help manage the magnitude of this project, you will find the project split into 2 parts.

  • Part 1 includes the ENGAGE, EXPLORE  and EXPLAIN components of the lesson; taking about 50 minutes. 
  • Part 2 includes the EXTEND and EVALUATE components of the lesson; taking about two 50-minute lessons or equivalent block period.


50 minutes

The EXTEND stage allows students to apply new knowledge to a novel situation. The novel situation in this case is the completion of the Exploding Popcorn Lab itself. At this point, students are engaged in the lesson and understand the basics of popping popcorn. During this stage, students write a hypothesis, identify variables, read the procedure and identify safety precautions (as shown here: Exploding Popcorn Investigation Experimental Design Plan Student Work) with their lab groups using the Exploding Popcorn Experimental Design Plan.

TEACHER NOTE: Once students complete the first page, it is important to conference with each table to check for procedural understanding. During this conference we discuss all facets of the investigation to ensure students understand how to proceed and the importance of safety while they carry out their investigation. I require all students to wear goggles and abide by safety guidelines because there are the hazards of glassware, heat, electricity, oil and projectiles in this lab. I also strictly enforce the "stay at your table" rule because there are so many potential trip, slip, fall, or hit hazards. Because this is a food lab, it is necessary to provide consistent reminders about not eating the lab! I always provide clean samples at the end of an investigation as a way to celebrate a job safely done. A reminder that this is not a safe lab to conduct at home without direct adult supervision is also necessary.

After conferencing with students, they begin to perform the investigation and collect data. Students are encouraged to take video of their investigation for the purpose of going back to collect data in slow motion:

Or super-slow motion:

Students make data measurements and observations. Students update their flowchart diagrams and then share their data with another group, in order to compare results and minimize potential errors by increasing the sample size. Together, students answer three data analysis questions (located in Part 6 of the Design Plan) to prompt them to think about how mass and volume change and whether the data supports their original hypotheses.

Teacher Note: Most students find this investigation to be highly engaging and challenging. For this students who need "a little something extra", review this section's reflection: Extensions to the Investigation for a some food for thought.


50 minutes

The EVALUATION stage is for both students and teachers to determine how much learning and understanding has taken place. As noted earlier, using a diagram as an assessment of learning is very effective for this lab: Exploding Popcorn Drawing Student Work. Having students amend, add data and explain their results as part of the diagram provides information about student learning. Depending on the learning objectives, literacy goals and time, I may have students communicate their results by completing conclusion questions: Exploding Popcorn Investigation PACER Argument Student Work as suggested in the last section of the Exploding Popcorn Experimental Design Plan. These questions also work as extensions for advanced students. Alternatively, students can complete a final lab conclusion or poster presentation. I don't usually go this far in evaluation since my learning objectives around measuring mass and volume changes are fairly basic and will be revisited in subsequent investigations.

Evaluation in this investigation can be augmented through classroom discussion. Because the investigation is complex, I find it very important to debrief by discussing data patterns and student conclusions with the whole class. The discussion component provides opportunities to grapple with the complexity of the concepts, ask and answer clarifying questions, and connect to past and future learning around the concept.