Wheel and Axle: Description
The wheel and axle is a simple machine in which the wheel is attached to the shaft (axle). The axle is a rod that goes through the wheel and the axle holds the wheel into place so the wheel can spin without moving out of place and is able to move. The input force is transferred to the axle, and the output force comes out from the wheel when it moves. When the axle is turned, the wheel moves a larger distance than the axle, so less force is needed to move the wheel, but the axle moves a shorter distance which means that you'd need more force to move it. The wheel and axle makes work easier by increasing the distance. In result to that, the force is decreased - in other words, the bigger the wheel, the less force is needed, and the smaller the wheel, the more force is needed. To add on, the wheel and axle is actually two machines in one, as you can use each part in different ways.
The bigger car has bigger wheels, which increases the distance. This decreases the amount of force needed to do a certain amount of work. However, the smaller car has smaller wheels, so it increases the force needed to move the same amount of distance.
Wheel and Axle: Invention
The earliest evidence of the wheel and axle comes from Sumeria (modern Iraq). This machine was invented in 4000 B.C. However, The inventor of the wheel and axle is unknown due to the fact that the wheel and axle was invented too long ago to be recorded. The earliest use of the wheel and axle was for pottery wheels. In 3700 B.C. (or the bronze age), people used the wheel and axle for wagon wheels. Additionally, the wheel and axle was used for winches (a device that is used to lift up objects with a rope, cable, or chain) on wells to pull water up to the surface. The other uses of the wheel and axle include wheelbarrows, spinning wheels, windmills, and pulleys. Today, the wheel and axle is used for many purposes such as cars and bikes.
Sources
McDougal Littell Science: Motion and Forces by McDougal Littell
Machines Make It Move by Stephen M. Tomecek
http://www.mikids.com/Smachines.htm
http://legacy.mos.org/sln/Leonardo/inventorsToolbox.html
http://teacher.scholastic.com/dirtrep/simple/wheel.htm
http://scienceforkids.kidipede.com/physics/machines/wheel.htm
http://df_blogs_media.s3.amazonaws.com/wp-content/uploads/sites/120/2014/10/000001-Hot-Wheels-MID.jpg - Picture
http://lh6.ggpht.com/rd6a_U8yMlBb4jn_BTwd01b6g5TGz2sbAM7bEy97OQFUIgVL6HYmsXb34U9oS4dVba-SZQ=s156 - Picutre
http://media.techeblog.com/images/tronbicycle.jpg - Picture
http://images.wisegeek.com/persons-hands-with-pottery.jpg - Picture
http://www.edheads.org/activities/simple-machines/glossary.shtml
Credits: Ariel L., Eugene J., Dominick S.
McDougal Littell Science: Motion and Forces by McDougal Littell
Machines Make It Move by Stephen M. Tomecek
http://www.mikids.com/Smachines.htm
http://legacy.mos.org/sln/Leonardo/inventorsToolbox.html
http://teacher.scholastic.com/dirtrep/simple/wheel.htm
http://scienceforkids.kidipede.com/physics/machines/wheel.htm
http://df_blogs_media.s3.amazonaws.com/wp-content/uploads/sites/120/2014/10/000001-Hot-Wheels-MID.jpg - Picture
http://lh6.ggpht.com/rd6a_U8yMlBb4jn_BTwd01b6g5TGz2sbAM7bEy97OQFUIgVL6HYmsXb34U9oS4dVba-SZQ=s156 - Picutre
http://media.techeblog.com/images/tronbicycle.jpg - Picture
http://images.wisegeek.com/persons-hands-with-pottery.jpg - Picture
http://www.edheads.org/activities/simple-machines/glossary.shtml
Credits: Ariel L., Eugene J., Dominick S.