Reflection: Developing a Conceptual Understanding Newton's 1st Law: Hammer, Nails & Inertia  Newton's Law Expo (2 of 9)  Section 3: Student Activity
Inertia is a word that has very little meaning to my students. I teach inertia as a resistance to change. We discuss that if I were to suddenly require a stricter dress code in class, the students would resist this change. But the meaning doesn't translate to the physical world until the students can experience this lesson. The bricks have a lot of mass and therefore have a lot of inertia. Since the massive bricks sit on top of a student's head it absorbs the strikes of the hammer. I've had success having my students think of inertia as a sort of absorbing force that every particle of matter has. The more mass an object has, the greater its absorbing force is.
Newton's 1st Law: Hammer, Nails & Inertia  Newton's Law Expo (2 of 9)
Lesson 2 of 12
Objective: Students will be able to test Newton's 1st Law using a hammer and nails.
This lesson is based on California's Middle School Integrated Model of NGSS.
MSPS2 Motion and Stability: Forces and Interactions
PE: MSPS22  Plan an investigation to provide evidence that the change in an object's motion depends on the sum of the forces on the object and the mass of the object.
DCI: PS2.A  The motion of an object is determined by the sum of the forces acting on it; If the total force the object is not zero, its motion will change (Newton's 1st Law). The greater the mass of the object the greater the force needed to achieve that same change in motion. For any given object, a larger force causes a larger change in motion (Newton's 2nd Law).
Science and Engineering Practices 7: Engaging in Arguments from Evidence
Crosscutting Concept: Cause and Effect
This activity can be used as a stand alone lesson or can be placed with eight other lessons, designed as an exposition to be experienced over three days.
Newton's Laws Expo contains:
 Coin Activity (1st Law)

Hammer/Nail Activity (1st Law) (today's lesson)
 Greek Waiter Tray (1st Law)
 Penny on a Coat Hanger (1st Law)
 Ping Pong Ball Activity (2nd Law)
 Balloon Racer (2nd Law)
 Paper Clip Racer (2nd Law)
 Skateboard Activity (3rd Law)
 Newton's Cradle (3rd Law)
I have also developed three demonstrations of Newton's Laws
Demonstrations
With this lesson students will engage in a short (eight minute) activity designed to demonstrate one of Newton's Laws. A stack of bricks will be placed on the head of a helmeted student, a hammer will drive a nail into wood on top of the bricks without the helmeted student feeling any of the hammer blows. The bricks will represent a mass with inertia and it will absorb any force applied to it (MSPS22). Since the mass of the bricks are so great the force needed to change its direction is also great (PS2.A). It will be the student's responsibility to use evidence recorded during the activity to determine that Newton's 1st Law is being expressed and inertia is the key to understanding what is happening (SP7). Each activity has been carefully chosen to replicate a specific effect, specifically that an applied force (hammer blow) is absorbed by a large mass (inertia) (CCC).
Setup
There are some basic materials that you'll need for today's activity:
 Hammer
 Nails
 Wood blocks
 Three bricks duct taped together
 Old bike helmet
Print out a copy of Station Markers. Tape the Station 2 marker card down to classroom locations students will conduct this activity. Each station marker identifies where the activity will take place and provides directions for completing the activity.
Print out a copy of Newton's Laws Exposition packet for each student. The packet includes directions and questions to answer. If you are performing this lesson as a single activity you will only need to print out Activity 2.
This activity is designed to accompany other Newton's Laws Activities. I run this unit as a threeday exposition. Day 1 is reserved for showing all the students the nine activities. Days two and three allow for an eight minute rotation. I typically have my students experience five activities (40 minutes) on Day 2 and four activities (32 minutes) on Day 3 followed by a recap of the events.
Resources (2)
Student Activity
Newton's First Law of Motion will be in effect for this lesson. Newton's First Law states that an object in motion will remain in motion and an object at rest will remain at rest, unless acted upon by another force. Objects that have mass, have inertia (resistance to change). The more mass an object has, the more inertia it has. Mass and inertia are directionally proportional. An object with a lot of inertia will resist a force being applied to it. According to Newton's 1st Law, an object at rest will stay at rest unless acted upon by another force. if the force is small compared to the mass of the object, the force imposed will have little or no observable effect.
Students do not know what specific law of motion they will be experimenting with. They will have to record what they see, gather evidence, draw a conclusion based upon that evidence and use argumentation with their peers about what law is being manipulated.
This activity has a student wearing an old bike helmet with several bricks stacked on top of the helmet. On top of that, a scrap of wood in placed on the bricks and a nail is driven into the wood by a hammer. The students are amazed that the student under the helmet hardly feels the impact of the hammer.
According to Newton's 1st Law, objects at rest unless acted upon by another force. The bricks stay at rest due to the force of the hammer. The large mass of the bricks resists (inertia) impacts of the small force of the hammer.
Directions
 Choose someone to wear the helmet.
 Place brick on top of helmeted student’s head.
 Place wood sample on top of brick.
 Hammer a nail into the wood.
Student Work Sample
Resources (1)
Resources (1)
Resources
Extensions
Newton's Law are expressed in a multitude of ways in the English language because Newton's original text ' Philosophiæ Naturalis Principia Mathematica', often referred to as the 'Principia', was written in Latin (as were all scientific articles in that time) and translated into English. As such, there are many different translations, causing confusion with students.
I teach Newton's Three Laws with this translations.
 An object in motion will reamin in motion and an object at rest will remain at rest  unless acted upon by another force.
 Acceleration is based on force and mass (F=ma).
 For every action there is an equal and opposite reaction.
To assit in teaching Newton's Law before this lesson is taught, I have included three Powerpoint lessons:
Resources (3)
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 LESSON 1: Newton's 1st Law: Coin Activity (Inertia)  Newton's Law Expo (1 of 9)
 LESSON 2: Newton's 1st Law: Hammer, Nails & Inertia  Newton's Law Expo (2 of 9)
 LESSON 3: Newton's 1st Law: Greek Waiter Tray  Newton's Law Expo (3 of 9)
 LESSON 4: Newton's 1st Law: Penny on a Coat Hanger  Newton's Law Expo (4 of 9)
 LESSON 5: Newton's 2nd Law: Ping Pong Ball Activity  Newton's Laws Expo (5 of 9)
 LESSON 6: Newton's 2nd Law: Balloon Racers  Newton's Law Expo (6 of 9)
 LESSON 7: Newton's 2nd Law: Paper Clip Racers  Newton's Law Expo (7 of 9)
 LESSON 8: Newton's 3rd Law: Skateboard Activity  Newton's Laws Expo (8 of 9)
 LESSON 9: Newton's 3rd Law: Newton's Cradle & Expo (9 of 9)
 LESSON 10: Newton's 1st Law Demonstration
 LESSON 11: Newton's 2nd Law Demonstration
 LESSON 12: Newton's 3rd Law Demonstration