##
* *Reflection: Developing a Conceptual Understanding
Newton's 2nd Law: Paper Clip Racers - Newton's Law Expo (7 of 9) - Section 3: Student Activity

The best strategy for teaching Newton's 2nd Law, that I have found, is to focus on the relationship between force(F), mass(M), and acceleration(a); which can be expressed as the formula F=ma or force(F) equals mass(m) times acceleration(a). In other words the force placed on an object is based on the objects mass and at what rate of speed it is traveling.

In a prior lesson Newton's 2nd Law Demonstration the students build a variable strip that allows them to manipulate the three variables contained within Newton's 2nd Law.

To build, cut three holes (about the size of a quarter) at each end and in the middle of a sentence strip. Label each hole as mass, force, and acceleration (in that order). A student can then insert their finger into the hole representing the variable they wish to remain constant. By placing their finger in the other hole they can raise or lower that value and the third variable reacts accordingly (either high or lower). So if force remains constant, an increase in acceleration requires a decrease in mass. In Newton's 2nd Law Demonstration each student must present their variable strip to their elbow partner and explain how the three variables interact.

*Best technique for teaching Newton's 2nd Law*

*Developing a Conceptual Understanding: Best technique for teaching Newton's 2nd Law*

# Newton's 2nd Law: Paper Clip Racers - Newton's Law Expo (7 of 9)

Lesson 7 of 12

## Objective: Students will be able to prove Newton's 2nd Law of Motion by racing paper clips.

*63 minutes*

This lesson is based on California's Middle School Integrated Model of NGSS.

MS-PS2 Motion and Stability: Forces and Interactions

**PE**: MS-PS2-2 - 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)
- 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) (this lesson)
- Skateboard Activity (3rd Law)
- Newton's Cradle (3rd Law)

I have also developed three demonstrations of Newton's Laws

Demonstrations

In this lesson, students engage in a short (eight minute) activity designed to demonstrate one of Newton's Laws. Large paper clips are dragged across a desk by a weight hanging off the end of the desk on a string (**MS-PS2-2**). The additional weights will not be seen as mass (m), but rather, increased force (F) (**PS2.A**). It will be the student's responsibility to use evidence recorded during the activity to determine that Newton's 2nd Law is being expressed, demonstrating the relationship between force (F), mass (m), and acceleration (a) (**SP7**). Each activity has been carefully chosen to replicate a specific effect (**CCC**).

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#### Set-up

*10 min*

Needed Material

- Large paper clips
- Yarn

Print out a copy of Station Markers. Tape 'Station 7' marker card down to the desk where you intend 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 7.

This activity is designed to accompany other Newton's Laws Activities. I run this unit as a three day exposition. Day 1 is reserved for showing all the students the nine activities. Days 2 and 3 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.

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#### Student Activity

*8 min*

Newton's Second Law will be in effect for this lesson. Newton's Second Law states that acceleration (a) is based upon force (F) applied to the object and the mass (m) of the object. A change in force or mass will change the object's acceleration. This law can be summed by the formula F=ma (Force = mass X acceleration).

Students do not know what specific law of motion they will be experimenting with. They have to record what they see, gather evidence, and argue about what law is being manipulated.

Directions

**TIP:** Adding additional paper clips should be considered an increase in *force* and not an increase in *mass.*

- Tie a paper clip to each end of a long string.
- Hook two more paper clips to one end.
- Place the single paper clip end in the center of the table.
- Hang the three paper clip end off the side of the table.
- Release the paper clips and record your observations.
- Add one more paper clip to the hanging end, repeat the experiment, and record your observations.
- Place as many paper clips of your choosing on one end, repeat the experiment, and record your observations.

**Student Work Sample**

#### Resources

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#### Extensions

*45 min*

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 using this translation.

- 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 assist in teaching Newton's Law before this lesson is taught, I have included three Powerpoint lessons:

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- UNIT 1: First Week of School
- UNIT 2: States of Matter
- UNIT 3: Periodic Table
- UNIT 4: Atomic Structure
- UNIT 5: Chemical Reactions
- UNIT 6: Forces
- UNIT 7: Density and Buoyancy
- UNIT 8: Motion
- UNIT 9: Solutions
- UNIT 10: Earth, Moon, and Sun
- UNIT 11: Solar System
- UNIT 12: Engineering and Design

- 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