Build a Compound Machine

We combined 3 of our simple machines into 1 compound machine. We combined our pulley, lever, and wheel and axle to create a machine with an AMA of 132. We were supposed to create a machine that had an AMA of 90. It was supposed to make lifting an object easier and more efficient. So we attached the wheel and axle to the pulley, and added a crank. After that we connected the lever to the pulley, which is what lifted the lever.

Our compound machine came out good because we had an AMA of 132 which was third in the class. One of the problems that we faced was not being able to pull up the weight as easy as it shouldve been able to because it was rubbing against the wood. So we changed the layout and it made it easier for the pulley to raise up the weight. Our changed that we made improved the AMA by 40, we made the second arm of the pulley go straight down instead of farther out to the side. We couldve used a stronger piece of string instead of the kind that we used, that wouldve made the rotation of the wheel and axle easier, and it wouldve been easier to move the weight.

I learned that the AMA is all depended on how efficient you are at putting your machines together. The hardest part was to think of a way to combine all of the machines, after that, it became easier to made the small adjustments on the project. Now I know that for the future projects, the most important part is to get a good foundation idea to build the project around. After that, the little adjustments that you have to make will come easier because you already have a grasp on the big idea of the project.

Simple Machines Blog

For this simple machine project we built 4 of the simple machines; the lever, wheel and axle, pulley, and inclined plane. For the pulley, the IMA that we were supposed to get was 2, and for the other 3 machines we were supposed to get an IMA of 6. We calculated the efficiency of each machine by dividing the AMA by the IMA and multiplying that by 100. After all the machines were tested and we had all of the percent's, we found the average percent for each group to see who did the best overall job.

For the wheel and axle we got 1st place with a 90% efficiency, for the inclined plane we got 2nd place with a 37% efficiency, for the lever we got 1st place with a 73% efficiency, and for the pulley we got 1st place with a 75% efficiency. Our average percent was 69% and the second place group only was 41% efficient. Some people would say that we were the obvious winner, but there are so many different things that can go wrong with testing the machines so its hard to actually pick a winner.

We didn't get 100% efficiency because its very difficult to measure perfectly and test it perfectly. For the pulley, there needed to be a horizontal line that could go through  2 of the pieces of string, which doesn't include the force arm. For all of the other machines we needed to measure a 6 to 1 ratio in order to achieve an IMA of 6. We could've payed more attention to the IMA before we started building so we could build the machine to specifically fit the IMA, instead of building the machines and then worrying about the IMA. That wouldve made it easier to change the IMA if it didnt come out with the results that we wanted when we tested. We also couldve tested earlier so we knew ahead of time what the IMA was, and if we needed to redo what we previously did.

Wooden Wheel and Axle, Noah and Dylan, Dec. 2013

Wooden Pulley, Nathan and Rob, Dec. 2013



Wooden Inclined Plane, Noah and Rob, Dec. 2013

Wooden Lever, Nathan and Dylan, Dec. 2013