Sunday, January 25, 2015

Simple Machines

I briefly mentioned the kids study of Simple Machines with my Halloween post, when Vicki mentioned that George was using a Class 2 Lever when using the wheelbarrow to carry our pumpkins.  I love it when the kids apply what they are learning.  :-)

For this unit, Jen and the kids used units from Teachers Pay Teachers, posters from the Mark Twain Media, the Thames and Kosmos Physics Simple Machine experiment kit...

and Simple Machines from the Step by Step Science Series from Carson-Delosa, Simple Machines by Deborah Hodge, and Explore Simple Machines by Anita Yasuda.

First, using a Movement and Simple Machines unit from Teachers Pay Teachers, they explored the various ways different objects move, including spinning, bouncing, rolling and tossing.  They tested different objects to determine which moved the best.

They found that pencils were the best spinners (out of pencil, marker, paperclip, straw, crayon, and ruler), a golf ball bounces higher than a football, a ping pong ball bounces higher than a tennis ball, and a ping pong ball bounces higher than a golf ball.   Marbles roll faster than golf balls, the yellow car rolled faster than the purple car, and the marble rolled faster than the yellow car.  And finally crumbled paper was easier to toss than a tissue.

They then read about forces and friction from Explore Simple Machines, and did a demonstration to create different amounts of friction and see the effect it would have on a car moving down a slope.  They recorded their results - it took .25 seconds for it to move down cardboard, .63 seconds to move down sandpaper, and .81 seconds to move down a towel.

The first simple machine they explored was Inclined Planes, and how they cut down the force needed to move something to a different level. 

They experimented with ramps by varying the angle of the ramp and seeing how far a car rolled down the ramp would roll.  Of course, it rolled the farthest with the steepest angle.

They then compared the result when an egg was dropped versus when it was rolled down a ramp, and determined how many pennies need to be added to a cup to be able to pull a car up a ramp and whether it would take more with a steeper ramp (it does).

They finished up inclined planes by doing the ramping up activity from the physics kit.

Next they explored Wedges, which is an inclined plane with one or two sloping sides that come together in a sharp point.   Wedges are used to split, lift, move, or stop an object.

They then explored wedges further by comparing whether a block of wood or a wedge of wood was better at keeping a door open, and seeing which was better at cutting a piece of clay. 

The next simple machines they explored were Levers.

After reading about levers, they did some experiments testing how the position of the fulcrum affected the amount of force was needed to lift something, identified fulcrums in common objects (like a stapler, broom, seesaw, wheelbarrow), and used a variety of levers such as a claw hammer to remove a nail, a screwdriver to open a can, a nutcracker to crack a walnut.  They did the Lever activity from the Physics kit.

The next simple machine they explored was screws.  A screw is a type of inclined plane, wrapped around a shaft, used to pull things together. 

The kids made their own screws by wrapping paper around a pencil, and made a paper helicopter that acted like a screw.

The next Simple Machine they learned about was Wheels and Axles.

Wheels and axles are two objects joined together in the middle, that rotate together.  After reading about them, they explored how much easier it was to move something using rollers, rather than pushing it over the ground, and how well a toy car moves with and without it's wheels.

Next they learned about Pulleys.

Pulleys are wheels that are used with ropes to lift and lower heavy things.    They made their own moveable pulley and did the pulley activity in the physics kit.
For the last demonstration, using a milk carton, pencils and rubber bands, they made a toy boat that would move through the water.  They didn't have too much luck getting it to move in the sink but later on in the tub they had better success.

They finished up by watching Bill Nye The Science Guy Simple Machines (available on youtube!).

The kids are now learning about the Solar System.  Hopefully it won't take me months to write up that one.  :-)


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