Teaching Newton’s Laws of Motion

Along with Albert Einstein, Sir Isaac Newton is probably one of the best known scientists in the world. Everyone knows his name, but few people can state his three laws of motion and even fewer can explain their application in the real world. Did you know Newton first presented his three laws of motion in 1686?

Many of the principles involved in teaching Newton’s laws of motion are abstract in nature and deal with concepts that students can not directly observe. Students come to physics class with various preconceived notions about the laws that govern the motion of objects in our everyday world. And many of these notions are incorrect. To overcome misconceptions, teachers need to incorporate a variety of teaching methodologies into their instruction. These should include physics demonstrations, traditional instruction such as lectures, and the use of practice exercises and student centered activities such as labs, practical work and discussions.

I always begin my unit on Newton’s laws with the classic demonstration of dropping two objects with different masses from the same height. I ask the students which object will hit the ground first and require them to write down their answer and explain their choice. This forces each student to think about their selection. Next, I stand on one of the classroom tables, hold the objects as close to the ceiling as possible and prepare to drop them…3, 2, 1….!! Having captured everyone’s attention I stop just before releasing the objects, jump off the table and tell the students that we should first discuss the forces that are acting on the objects. Now I can introduce the concepts: What is a force?, What is gravity?, What is the difference between mass and weight? Before finally dropping the objects, we discuss the possible results and I give everyone a chance to revise original choices.

In the following classes we move on to further instructional material that I’ve developed, including online labs using PhET Interactive Simulations. These simulations require no set up, provide accurate and repeatable results, and are designed based on research into how students learn. Students also learn how to perform quantitive analyses of the motion of objects, including the use of Newton’s second law of motion: F = m • a. All my PhET lab activities, along with problem sets and exercises with notes and solutions for a variety of second law scenarios, are available from my Teachers Pay Teachers store.

These activities and exercises are designed for use with the instructional videos on my YouTube channel. Each video provides an in-depth explanation of the concepts covered in the materials. The videos bring the concepts to life, especially for students who are learning from home during the pandemic.