Forces are everywhere — students push desks across the floor, balance stacks of books, or ride elevators without thinking twice about the physics at play. But how do you take these everyday experiences and turn them into clear, measurable lessons about Newton’s Laws?
That’s where the Newton Scale comes in. This simple tool turns invisible pushes and pulls into visible numbers, letting students test their own strength, puzzle through equilibrium, and even measure what happens when an elevator starts to move.
What the Newton Scale measures:
A Newton Scale (platform scale) reports the normal force between the person/object and the scale — i.e., apparent weight. The reading changes whenever the normal force changes (for example, when an elevator accelerates), even though the force of gravity itself remains constant.
Here are three hands-on activities (adapted from physics teacher Bree Barnett Dreyfuss) that will have your students measuring, questioning, and discovering Newton’s Laws in action.
Activity 1: Newton vs Newton
Newton’s Third Law tells us that forces always come in equal and opposite pairs — but that can be a tough sell when students think in terms of “who’s stronger.” With two Newton Scales, you can settle the debate once and for all.
Have students hold their scales back-to-back and run three quick trials:
-
Student A pushes first.
-
Student B pushes first.
-
Both push at the same time.
Each time, both scales read the same force.
Ask Your Students:
-
-
-
- How can the forces be equal even if one student started first?
-
What would happen if one student suddenly stopped pushing?
-
-
This eye-opening demo makes Newton’s Third Law visible and clears up one of the most persistent misconceptions in physics.
Activity 2: The Normal Force Mystery
Is the Normal Force always equal to the force of gravity? Students often assume so — until they measure it directly.
Stack two Newton Scales with books or blocks in between and compare the readings. Try swapping the books and ask what changes. Can the bottom scale ever show less force than expected?
Ask Your Students:
-
-
-
-
What does each scale actually measure?
-
Did the books somehow get heavier when we swapped them?
-
How does this compare to the gravitational force?
-
-
-
This activity helps students distinguish between weight (the downward force of gravity) and the Normal Force (the upward support force provided by a surface). It’s a hands-on way to dig into mechanical equilibrium and why forces don’t always behave the way students first imagine.
Activity 3: Riding with Newton
Why do you feel heavier or lighter in an elevator? With a Newton Scale, students don’t just feel it — they measure it.
Have a student stand on the scale during a short ride. Ask them to note the reading when the elevator:
-
-
-
-
Stays still
-
Starts moving
-
Slows to a stop
-
-
-
They’ll see the scale reading increase or decrease depending on the acceleration, then return to “normal” at constant speed.
Ask Your Students:
-
-
-
-
When do you weigh more — speeding up or slowing down?
-
Why does your weight feel different even though gravity hasn’t changed?
-
-
-
This activity connects Newton’s Second Law to a familiar, real-world experience, giving students measurable evidence of how acceleration affects forces.
Teacher Note (Formula Box):
Apparent weight is the normal force N on the person:
-
-
-
- N=m(g+a) (upward aa)
- N=m(g−a)N=m(g−a) (downward aa)
- At constant speed (a = 0), N=mg
-
-
Why the Newton Scale Belongs in Every Classroom
From strength contests to mysterious book stacks to elevator rides, the Newton Scale transforms everyday experiences into meaningful physics lessons. It’s durable, easy to use, and versatile enough for middle school and high school classrooms alike.
By letting students measure what they feel — and then challenging them to explain it — you give them a hands-on way to make Newton’s Laws real, memorable, and fun.
About the Author
Bree Barnett Dreyfuss has been teaching Physics and AP Physics at Amador Valley High School for almost 20 years. She has been involved with the STEP UP program since 2018, helping to increase the number of undergraduate women in physics and supporting inclusivity in high school physics classrooms.
