Iris Valdez
Cal Poly Pomona
SCI 210 Lab
Flight Attendants!
Objective: To build a catapult and observe the relation of the angles of trajection and the distance traveled by the catapulted object.
Information:
A primary objective that will be demonstrated in this activity is
Newton's First Law of Motion. This law states that, "An object at rest
tends to stay at rest and an object in motion tends to stay in motion
with the same speed and in the same direction unless acted upon by an
unbalanced force." A catapult will act on an object by using a spring
force to change the marshmallow from an object at rest to an object in
motion.
An object that is catapulted has two vectors that work at the same
time. One vector is represented vertically, while the other is
represented horizontally. There are also two forces that act on an
object. One force works against the object horizontally through air
resistance. And the force of gravity works downwards on the object.
Materials:
-Ruler or Popsicle stick
-Wooden block approx. 2" x 2"
-Plastic Spoon
-Plastic Mailing Tape
-Marshmallows
-Paper and pencil
-Protractor
-Meter stick
Procedure:
1) Place the wooden block at the end of the ruler or popsicle stick.
Place the end of the spoon above the block so that the bowl of the
spoon is above the ruler.
2) Tape the objects together.
3) Align the catapult so that the extending end of the ruler is against a wall. Place the marshmallow on the spoon.
4) Pull the spoon down and let the marshmallow fly. Measure the
distance from the end of the block. This launch represents a 90°
angle projection from the open side of the block.
5) Using your protractor, tilt your block so that a 75° angle is
represented on the open side of the block. This will represent your
catapult at 75° of projection. Launch a marshmallow and record this
distance.
6) Use the protractor to measure 60° from the open side of the
block and tilt the block to match this angle. This will represent
60° of projection. Launch a marshmallow and record the distance.
7) Measure 45° from the open side of the block for 45° of projection. Launch and record the distance of the marshmallow
8) Lastly measure 30° on the open side of the block for a 30°
projection. Launch and record the distance of the marshmallow
Discussion:
Which angle of trajection did the marshmallow fly the farthest?
The angle at which the marshmallow should have flown the farthest is at 45°.
At which angle did the marshmallow fly the shortest distance?
The angle at which the marshmallow should have flown the shortest distance would be at 90°.
Were you surprised by the data and your thoughts on what would have happened?
Sources:
http://familyfun.go.com/parenting/learn/activities/feature/famf199611_learnproj1/famf199611_attendants.html
http://www.glenbrook.k12.il.us/GBSSCI/PHYS/CLASS/newtlaws/u2l1a.html
http://www.glenbrook.k12.il.us/GBSSCI/PHYS/CLASS/newtlaws/u2l2b.html
http://school.discovery.com/lessonplans/programs/motionforces/