Newton's Third Law

Jerri Chavis                   Langston Hughes
                               226 W. 104th
                               Chicago IL 60643
                               (773) 525-5075

Objective:

This mini teach is designed for grades K-2.  Children will use inquiry and 
observation skills to determine Newton's Third Law of Motion; for every action 
there is a reaction; for every force there is an equal and opposite force.

Materials Needed:
    
    (see below group & individual activities)

Individual Activities:

(Stations 1-6 are individual student stations)
Each station should have an instruction sheet with helpful illustrations.

Group Activities: 

Balloon Races
Balloons (different shapes & sizes)
Straws, Tape, String 

Canister Explosion 
Alka-Seltzer(Bicarbonate), 2-35-mm film canisters 

Skate Board 
2-Skate Boards or 2-Office Chairs 

Wrap up surprise 
2-Soft drink cans; 2-3 firecrackers (teachers' use only)

===============================================================================

Individual Stations:

Station #1- Stomper Truck
Stomper Truck, 4x6 piece of cardboard paper, BB's/beads 
1. Place cardboard on top of the beads. 
2. Next place stomper truck on top of cardboard and turn stomper on. 
Ask Question: What do you think will happen?  
                                                 
Station #2- Newton Scales
Newton Scales-2
1. Connect spring scales together
2. Person #1: pulls so that the scale stops on the number 20.
3. Person #2: does not pull.
Question: What do you think each scale will register?

Station #3- Books
Books
1. Person #1: Places books in person #2 hands.
2. Person #2: extends palms up to hold books.
3. Person #1: quickly remove books from person #2's hands.

Station #4-Pyramid 
(2-person exercise)
1. 2 persons stand facing each other with palms of hands touching each other.
2. Each person will continue touching and moving feet backwards until they
   form a triangle.
Question:  Who's pushing whom? 

Station #5-Weight Scales
Bathroom Scales
1.Each person stands on scale puts hands under lip of table.  Pull upward on the 
edge of the table. 
Question: How much do you weigh while doing this? 
2. Next, while standing on scales push down on table top. 
How much do you weigh while doing this? 
         
Station #6-Step Off
1 Skateboard
1. Step upon the skateboard.
2. Take one step forward, as if walking off the skateboard.
Please have someone hold onto your hands!!!
Question: Describe what you think will happened?

Strategy:

Group Activities
1st Group Activity: Balloon Race will serve as opening activity which allows 
group to do a cooperative activity together.  This activity demonstrates 
"Newton's Third Law of Motion."  By showing the students, when the air in the 
balloon is pushed out of the balloon, the escaping air pushes forward on the 
balloon.  Allow students to test different hypotheses.  What would happen if the 
balloons were filled with more air?  What would happen if the balloons were 
raced up hill? 

How To Construct Balloons For Race:
Determine how long the string needs to be for races (5-6 ft. per racer).  Feed 
string through the straw (useful hint: make a threader out of floral wire, when 
finished it should look like a bobbie pin; this device needs to be longer than 
the straw you will be using, it allows for easier feeding of string through the 
straw).  Attach straw and string to balloon with tape.  Each contestant's string 
is attached to the wall/board and held in one hand.  The other hand is holding 
the balloon that will be released at the start of the race. 
 
2nd Group Activity: Station #3-Skate Board
2-Skate Board (you can use in place of skateboards 2-Office Chairs).  This 
activity has two persons standing on skateboards and their palms touching each 
other.  Then they push off from each other.  Ask what do you think will happen? 
Each person should be propelled backwards (opposite directions).  If you do not 
have a skateboard use 2 office chairs and have persons sit facing each other 
with palms touching.  Ask them to push off and see what happens.    

Performance Assessment:

(SURPRISE EXERCISE):  Introduce students to soft drink device consisting of two 
cans and one firecracker.  Then ask them what do they think will happen when the 
firecracker is placeed between the cans and lit.  Have them write their 
conclusions in their journals.  This will allow you to see if the children truly 
understand:  For every action force there is an equal and opposite reaction 
force. 

Alternate Activity:  (You can use the two 35mm film canisters and Alka-Seltzer 
(Bicarbonate in place of the firecracker activity if you like; same conclusions 
will be drawn).  The firecracker is just more dramatic.  In order to use film 
canisters, half fill the two 35mm canisters with H2O.  Close the lid on one of 
the canisters and lay it down on the table on its side.  Add the 1/2 tablet of 
Alka-Seltzer quickly to the 2nd canister.  Quickly put the cap on and lay it 
quickly on its side with the lids facing each other.  This is an alternate to 
the use of a firecracker in class. 
             
Conclusions:

From a philosophical point, for every action in life there is a reaction.  
If you touch the world gently....the world will touch you back gently.  If you 
touch the world harshly the world will touch you harshly. 
                   
References:

Conceptual Physics by Paul Hewitt
Encarta