Newton’s First Law of Motion and Inertia
René Ornelas-Young, Cathy Zehnder, and Christy DelosSantos
Introduction to Physical Science, C. Dianne Phillips, Instructor
Introduction:
To understand and learn the meaning of Newton’s First Law of Motion, otherwise known as the
Law of Inertia, students will follow three interactive activities. The 1st activity is the Egg Drop
involving inertia whereas; “An object at rest will remain at rest unless acted upon by an
unbalanced force.” The 2nd activity, Moving Magic Marbles, and 3rd activity, Marble Roll,
involves inertia and momentum whereas; “An object in motion will remain in motion in a
straight line at a constant speed unless acted upon by an unbalanced force.” Introducing these
interactive activities will allow students to gain the knowledge and see that Newton’s First Law
of Motion is a part of their everyday life. To enhance the students’ understanding of Inertia and
the unbalanced force prior to the activities, provide a visual demonstration of an occurrence the
students may see or experience in everyday life. Exploring science can be fun as well as
educational.
An example for a visual demonstration is to have a student stand still in front of the class,
explain that the floor pushes upward and gravity pulls downward and these two forces acting
upon the student are balanced. Give the student a slight push to the side and explain that the push
is an unbalanced force.
Grade level: 4th-7th
I.
Learning objectives
a.
b.
c.
d.
e.
f.
g.
h.
i.
Students will learn about :
Determining how an object remains at rest until acted upon by an unbalanced
force by conducting the Egg Drop experiment.
Determining how the momentum can transfer to an item at rest by conducting
the Marble Magic experiment. Students will also learn by apply several
marbles at rest and experience how the momentum transfers to each marble
until the momentum reaches the last marble in which the last marble will
continue in motion until acted upon by an unbalanced force. All previous
marbles will be at rest after the momentum is transferred.
Determining the net force of an object in motion by conducting the Marble
Roll experiment.
The difference between balanced and unbalanced force.
To show how force affects motion of an object.
The transfer of momentum from one object to another.
Momentum can pass from one object, through a second, and into a third.
The total amount of momentum at the beginning will stay the same.
The various sizes of the marbles will show how mass effects inertia and its
motion
II.
Learning Skills
III.
Materials Needed:
Students will be able to:
a. Expand their knowledge base, and learn how this can apply to daily life.
b. Students will be able to learn how to safely conduct their own experiments to
help in their understanding of Newton’s Laws of Motion.
c. Students will learn how make observations and interact and discuss
information with other classmates.
Activity 1: Egg Drop
Raw Eggs
Drinking Glass(s)
Pie Pan(s)
Cardboard Tube (from paper towel or toilet paper roll)
Water or tissue (add to cup to avoid breakage of egg)
Paper Towels for cleanup
Activity 2: Marble Magic
2 Yardsticks
Tape
Several Marbles
Activity 3: Marble Roll Activity
Pen
Meter stick
Tape
Protractor
Scissors
10cm by 70 cm piece of poster board
Marbles of various sizes
IV.
Procedure:
A. Introduction/Enlightenment: A short PowerPoint explaining the concepts
of Newton’s First Law-Inertia. Show a visual example explaining the
difference between balanced force and unbalanced force. (Example noted
above)
B. Exploration: Each student should be given the opportunity to explore all
three of the interactive activities to gain knowledge of how inertia works.
Activity 1
1. Fill the large drinking glass about three-quarters full with water and center the
pie pan on top of the glass. Place the cardboard tube on the plate, positioning
it directly over the water. Carefully set the egg on top of the cardboard tube.
2. With your writing hand, smack the edge of the pie pan horizontally. It’s
important that you use a pretty solid hit.
3. Your astonished students will watch the egg plop nicely into the water. It’s
even more fun to watch your students try to drop the egg. Be prepared for a
few misses or should I say, messes. Science is so cool!
Activity 2 appeal of 2 yardsticks glued to the kitchen table).
1. Tape the yardsticks to a level tabletop so they sit side by side and about ½”
apart.
2. Put 2 marbles in the middle of the stick (1/2” track) and space the marbles a
few inches apart.
3. Flick a marble so that it rolls and hits the other one. Notice that the one that
had been rolling stops while the one that had been at rest now rolls! The
momentum of the rolling marble transfers to the other one, setting it in
motion.
4. Now put 2 marbles on the track so that they touch, flick a marble into the 2 at
rest. Notice that the rolling marble stops, the middle marble stays put, and the
end marble rolls. The momentum transfers through the middle marble into the
end marble, setting only the end marble into motion.
5. Try this with any combination: 1 marble into 4 or 5, 2 marbles into 3 marbles
and see the effects of transfer and motion.
Activity 3
1. Construct a double ramp using these following steps:
Use the pen and measuring stick to draw two lines down the poster board
3cm from each side.
Fold up the edges of the strip at the lines you drew in step 1 to make
outside rims.
Mark each 1 cm down the center of the poster board strip.
At the 15-cm and 25-cm marks, cut diagonal slits in the rim on both sides.
(see figure below)
Bend the strip at each slit to form an incline of 60 degrees at each end of
the strip. Use tape to secure the overlapped edges of the rims.
2. Set the ramp on the table. Use tape to secure the short side of the ramp to a
stable vertical structure such as a wall. Tape the middle of the ramp to the
table. The tall portion of the ramp should be stable enough to stand
unsupported, but use a book to support it if necessary. ( See diagram on the
following page)
3. Hold the marble at the 2nd cm mark from the top of ramp A (13cm from the
base of the small ramp).
4. Release the marble and allow it to roll down ramp A.
5. Observe the height the marble reaches on ramp B. Using the marks on the
ramp measure the distance the marble travels from the base of ramp B to its
highest point. Record the measurement in a Distance Data table.
6. Repeat these steps several times and record the results each time.
7. Now average these results.
8. Try using the larger marbles and compare the results you get with the results
from the smaller marble roll.
V.
Results:
Activity 1-The pie pan is met with an unbalanced force when hit moving
sideways and applying an unbalanced force on the tube, the egg is still at rest for a
split second before the unbalance force of gravity pulls it downward into the
glass.
Activity 2-The marble(s) transfer momentum to the marble(s) at rest causing the
moving marble(s) to rest and resting marble(s) to be set in continuous motion
until acted upon by an unbalanced force.
Activity 3-The distance will vary depending on the size of the marble used and
the surface of the ramp.
VI.
Conclusion:
Review the outcomes with the students to evaluate their understanding of
Newton’s First Law of Motion. Hand out a worksheet and have the students
explain Inertia and how it is considered in everyday life. Have them explain the
outcome and reasons for what happened in each activity.
Activity 1- Review the concept of unbalanced force and the effects it had on the
objects at rest.
Activity 2- Review the meaning of motion and the transfer of momentum.
Activity 3- The ramp structure is similar to the one designed by Galileo. Galileo
discovered that when a ramp’s surface is very smooth, a ball will roll down one
side and rise up to almost the same height on the other side. The amount of
friction the ramp will have depends on the material chosen to construct the ramp.
A smooth surface will allow for the marble to roll much more easily than if the
ramp were made of sand paper. Once the marble is released, the force of gravity
pulls the marble down. When it reaches the bottom of ramp A the marble had
reached its maximum velocity, and would have continued to move at this velocity
if no forces acted on it. This is the basic law of inertia. In this experiment forces
acted upon the marble, including friction between the marble and the poster
board. As the marble rolled up the ramp, gravity pulled down on it, also causing
deceleration (a decrease in velocity per unit of time).
VII.
Standards:
K-8
These are also at the 4th grade level
P.6.PS.1 Analyze how force affects motion:
One-dimensional (linear)
Two-dimensional (projectile and rotational)
P.6.PS.2 Explain how motion is relative to a reference point
P.6.PS.3 Compare and contrast among speed, velocity and acceleration
P.6.PS.7 Design and conduct investigations demonstrating Newton’s first law of
motion
VIII. Evaluation:
(Example from one Evaluation):
A. Students answered discussion questions readily.
B. Students understood the concept of Newton’ First Law.
C. The Egg Drop involved a few minor accidents involving the egg and the floor
but this added to the fun and excitement of the overall experiment.
D. Students to complete the worksheet.