When teaching Newton's Three Laws of Motion to my sixth graders, it is absolutely essential that we model each principle. Shortly after seeing these forces in action, students start to realize that much of Newton's philosophy was based on common sense from real-life experiences.
For Newton's third law, we used several examples to model how forces act in pairs and how these active and reactive forces cause motion.
After completing quick notes to keep in our science binders, we watched videos and analyzed how these motions from the students' shared experience and knowledge showed Newton's third law in action.
Our first demonstration was to simply inflate a balloon, then release it and let it zip around the room. I explained how the contracting sides of the balloon forced out air. The reactive force propelled the balloon forward, causing it to fly around the room.
Before the lesson, I did a quick search on YouTube and bookmarked some videos of similar active and reactive forces. I chose to show a jellyfish and a rocket. After watching the videos and briefing the students on the forces in them, the students recorded their observations in their notes for later reference.
The culminating activity of this lesson is a lab demonstration. For the lab, we borrowed scooters from the Physical Education department. We used masking tape to mark off starting lines for the two scooters, then we demonstrated how force applied from one scooter causes both scooters to move. The lab is explained in more detail on the lab sheets below.
This lesson was a success in our classroom, both in terms of student engagement and student understanding. It helps, however, to have a little extra help with overseeing the students while they setup and demonstrate the scooter portion of the activity!