Mass versus Weight: A unique STEM approach

I regularly incorporate NASA activities into my physical science curriculum.  In this post, I cover how I introduced a NASA lesson on  Mass vs. Weight into my classroom.  This particular lesson can be found on the NASA education page.  While this post will focus on physical science, the lesson could be easily incorporated into other disciplines.

Students commonly misuse the terms “mass” and “weight”.   The principal objective of the lesson is for students to properly define and explain the difference between the two concepts.

KEY CONCEPT: Mass is the amount of matter in an object and weight is a force due to the gravitational pull on an object.  Mass is constant despite exposure to gravity, while weight is a measurement of force upon an object based on gravitational pull.  This difference is often difficult for students to grasp because they have a singular experience–gravity on planet Earth.

The activity, Mass versus Weight (on the NASA website), explores the concepts of mass, weight, forces, Newton’s Laws, gravity  and micro-gravity across four lessons.

In the first lesson plan, students are introduced to three astronauts through reading exercises and video and provided and overview of concept.  My students felt connected to the astronauts and enjoyed watching the videos that explained the experiments on the International Space Station (ISS) and how the micro-gravity changed the behavior of the activity.

The first activity, Stretching Mass, required students to record mass and volume and observe the gravitational pull on a full versus empty Capri-Sun juice pouch. Predictions were made regarding the result of the same test conducted in  a micro-gravity environment.  Following their predictions, students watched videos shot on the ISS in which the astronauts carried out the same experiment.   The students enjoyed seeing the changes and verifying their predictions.IMG_7605video of astonaut 2
In this picture, Nicole Passonno Stott (NASA astronaut) performs the same experiment with Capri-Sun juice pouches in space.

In the second activity, Air-Powered Mass,  students created paper containers to hold pennies (change in mass).  A series of straws were placed horizontally in a line below the box to create a roller belt.  A balloon pump was used to force burst of air against the container and propel is over the straw rollers. The experiment was repeated with additional pennies (increase in mass) added between each set.  Students recorded the mass and distance traveled during each set.  Instructor-led presentations covered mass, momentum, Newton’s laws of motion and forces using the experiment as  a case study.IMG_7610
TIP:  Keep the type of air pump consistent for each group.  I used two different air pumps and one didn’t push air out as consistently as the other.FullSizeRender
Students were prompted to make predictions how this same activity would work in a micro-gravity environment, then watched video of two astronauts preforming the experiment.
video of astronaut pictures
Here Robert Brent Thirsk and Koichi Wakata perform the experiment with a large air gun.  Students observed that the air pushed on the container the same way.  Due to a lesser gravitational pull, the object stayed in motion and did not stop.

The series continues with a lesson on Accelerating Mass and an activity,  Designing Your Own Experiment.   I was unable to fit this lesson in due to time constraints.  I did not find the omission of this lesson as a detriment.  My students demonstrated an understanding of the concepts, mass versus weight, and had an early introduction to Newton’s laws and forces.

Stay tuned for my next post on how I incorporated NASA’s Environmental Control and Life Support System (ECLSS) engineering design challenge activity into my curriculum at the end of my elements/compounds/mixtures chapter.  My students loved it so much they wanted to do it again!!



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