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LessonGrades 5 - 7

What Is Newton's First Law?

Two photographs: A man in a blue uniform and cap swings a bat to hit a baseball. A woman buckles a baby into the straps of a child safety seat in the backseat of a car.Newton's laws explain the movement of everyday objects.

Students are introduced to the concepts of force, inertia and Newton's first law of motion: objects at rest stay at rest and objects in motion stay in motion unless acted upon by an unbalanced force. Examples of contact and non-contact types of forces are provided, specifically applied, spring, drag, frictional forces, and magnetic, electric, gravitational forces. Students learn the difference between speed, velocity and acceleration, and come to see that the change in motion (or acceleration) of an object is caused by unbalanced forces. They also learn that engineers consider and take advantage of these forces and laws of motion in their designs. Through a PowerPoint® presentation and some simple teacher demonstrations these fundamental science concepts are explained and illustrated. This lesson is the first in a series of three lessons that are intended to be taught as a unit.

Engineers apply basic physics concepts such as Newton's laws of motion to a wide range of problem-solving situations, including the design of structures and vehicles. For example, engineers design the seat belts in cars to keep passengers from being thrown from vehicles in the event of a crash, which occurs as a consequence of Newton's first law. Learning how Newton's laws apply in everyday situations enables students to describe how objects move and helps prepare them for the study of more complex physics concepts.

After this lesson, students should be able to:

  • State and explain Newton's first law of motion.
  • Identify and give examples of (types of) forces.
  • Compare and contrast speed, velocity and acceleration.
  • Apply Newton's first law to explain the effect of applying a force on an object.  

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