Inertia

Maeola Walker                  Chicago Board of Education
                               1819 W. Pershing Rd.
                               Chicago IL 60609
                               (312)535-3730

Objective:

This lesson is for primary students.  The main objective of this mini-teach is 
for students to learn and understand what inertia is.  They will learn the 
difference between inertia for objects at rest and objects moving in a straight 
line. 

Materials Needed:

Two dolls (Barbie & Ken), two carts (skates, skate board)

Strategy:

Place one doll in each cart.  Secure one doll with a rubber band, tape or 
string.  Push the carts into a wall.  Ask the students what happened and why.  
(Doll not secured should fly out or fall forward).  Talk about seat belts. 

Materials Needed:

Two identical coffee cans and a hammer.

Strategy:

Fill one of the cans with a mass (a piece of metal) that will stay in place.  
Keep top opening of the cans away from the class when placing them on top of 
table or smooth surface floor.  Tap one can lightly with the hammer, and ask 
students to keep their eyes on the can.  Next tap the second can with the 
hammer, ask the students to watch that can and ask them which can rolled the 
farthest ... why?  (The can with the mass will not go as far as the empty can 
because the full can has a lot of inertia and tends to stay at rest). 

Materials Needed:

A 2 X 4 block of wood, a dowel & a hammer

Strategy:

Drill a hole the diameter of the dowel through the block of wood.  Insert the 
dowel loosely into the block and hold the block precariously suspended.  Hit the 
top of the dowel with the hammer.  You will drive the dowel through the block, 
but the block of wood will not move since its inertia will try to keep it in 
place, even though that place happens to be in mid air.  

Materials Needed:

Large size textbook & friction beads


Strategy:

Place a book on top of a large size desk top.  Give the book a thrust with one 
hand and see how far the book will slide across the desk top.  Next sprinkle 
beads on desk top then place the book on the top of the beads, now see how far 
the book will slide across the desk top.  The book has inertia in each case and 
tend to keep moving.  The reason the book stops in one case is friction. 

Materials Needed:

A three foot length of dowel & a 2 X 5 board

Strategy:

Drill a hole the diameter of the dowel in the board.  Cone shape one end of the 
dowel.  Place the dowel on the floor with the flat end of the stick (dowel) on 
the floor.  Next place the board on the cone end of the stick until at rest.  
Raise the stick into the air and pound stick heavily onto the floor.  The board 
should slide to bottom of stick until it hits the floor...why?  (because of the 
inertia in the board.) 

Materials Needed:

Three 3 X 5" boards & a hammer

Strategy: 

Stack the boards on top of each other.  Hit the bottom board horizontally with 
the hammer.  Watch the two boards on top drop into place.  Repeat the process 
with the second board and watch the top board drop into place. 

Materials Needed:

Felt or cloth table cloth
8  Meter sticks
4  Clamps
2  Pool Balls
1  Pool cue (wood dowel)
1  One marker & a quarter

Strategy:

Stretch out the table cloth taut and pin it down with the meter sticks and 
clamps.  Put an eight inch circle in the center and another 14 inch circle 
around the eight inch one. 

Place the pool ball in the center with a quarter on top of it.  Challenge the 
students to knock the quarter outside the small circle.  Students may not hit 
the quarter with the pool ball they are shooting at it, and they may not start 
closer than the large circle. 

Materials Needed:

A 5-gallon bottle, crochet hoop & ink pen with a flat top


Strategy:

Place the bottle on a table top.  Next balance hoop on bottle top then balance 
pen on top of hoop.  Snatch the hoop from the inside real fast and watch the pen 
drop into the bottle.  The only force acting on the pen is gravity which pulls 
it straight down. 

Performance Assessment:

Students' performance assessment will be measured by their participation and 
interest in each activity followed by a test on inertia.  The students will 
leave the class with a through understanding of Newton's first Law of Motion.