Catapults, Gears and Pulleys For Your Homeschool Science Curriculum

Simple machines always fascinate me and I'mmachines. The belt helps convey power from one
sure they will fascinate you enough to tell yourpulley to the other. Many vehicles use this
parents or homeschool teacher to add them tomechanism to relay power to all wheels. When
your homeschool curriculum. In the followingpulleys of different sizes are used, torque (driving
experiments, I am going to show you how topower) can be traded for speed and vice versa.
build some simple machines with household articles.The following homeschool curriculum experiment
The following homemade simple machine is a kindthat I have designed will help you see how.
of a lever that helps lift a ping pong ball andCool Pulley and Belt Mechanism: Find an old roller
various heavy objects. I will teach you to build it inskate with the wheels protruding from the sides.
no time and to make your homeschool curriculumThe new inline models will not work. Place the
exciting.skate on its side so that it rests on one set of
Easy Popsicle Catapult: Place five large sizedwheels and the other two wheels are facing
popsicle sticks one above the other and bindupwards. Wind a rubber band over these two
them tightly together by winding rubber bands onwheels. You are using the rubber band as a belt.
both ends. Now bind two large-sized popsicleWhat happens when you rotate one wheel
sticks in the same way but only wind the rubberclockwise? Which way does the other wheel
bands around one end. Pull the free ends of therotate?
sticks wide apart in the shape of a "V."Now remove the rubber band from one wheel,
Now insert the stack of five in between the twokeeping it still wrapped around the other wheel.
sticks forming a V and push it towards the rubberGive the rubber band a twist so that it looks like
band end, widening the angle of the V. Nowan 8 and put it around the wheel. Now rotate one
secure the intersection with rubber band. Next,wheel clockwise. Which way does the other wheel
place the V on its side so that one arm of the Vturn? I have now given you a fair idea of how
is resting on the table. On the other arm, glue abelts are used to make pulleys or wheels turn in
cap of a milk jug with the open end up. This capthe desired direction.
holds the projectile, which could be a ping pongBall Bearing Experiment: Take a clean paint can
ball. Just a flick of the catapult's arm will send thewithout the lid. You will see that after removing
ping pong ball in the air. Have fun!the lid there is a rim that is grooved. Now place
Gears are wheels having teeth along their rims.an old heavy book or a similar object on this
These teeth fit into each other so that whengroove. Try to turn the book. You will notice that
force is used to turn one wheel the same force isthe book does not easily turn on the can.
relayed to the other wheel.Place some marbles all along the rim and place the
Bottle Cap Gears: Flatten out two bottle caps insame book on the marbles. Now try to turn the
such a way that they are round in shape andbook. Is it easier? However there is still friction
their edges are still wavy. Now make holes in thebetween the marbles. How about putting a few
center of both and nail them to a wooden boarddrops of cooking oil in the ridge of the rim (this
in such a way that their wavy edges are incan get messy, so you may use a wooden sheet
contact with each other, forming the teeth of theor a chopping board instead of a book).
gears. When you rotate one cap, the other willNow place the object over the marbles and turn
also rotate, but in the opposite direction. This is ait. Is it easier to turn the book? The above
cool example of simple gears.homeschool curriculum experiment will give you an
Some gears have wheels of unequal diameters. Inidea about how ball bearings are used in simple
such a case, when the larger wheel turns oncemachines to reduce friction.
the smaller wheel turns many times andClick the link below to check out the free
therefore magnifies the force."Homeschool Parent's Guide to Teaching Science",
The pulley and belt combination is used in manyfor more great science experiments and activities.