# complex machine

Complex (or compound) machines combine one or more simple machines together. The result combines properties and functions of the component simple machines and usually provides additional functionality to what the component simple machines can provide.

Compound Machine : Two or more simple machines working together to make work easier.

• Stapler – lever, wedge
• Can opener – lever, gears, wheel and axle, wedge
• Wheelbarrow – wheel and axle, lever, inclined plane
• Hand drill – wheel and axle, gear, screw, lever
• Bicycle
• Perpetual Motion Machines

Sample examples of complex machines
Rube Goldberg was famous for combining dozens of simple machines into very complex machines that preformed some very simple tasks. Today, any machine that is more complicated than necessary is often described as a “Rube Goldberg Machine” after this designer and engineer.

• grasshopper escapement – an unusual, low-friction escapement for pendulum clocks invented by British clockmaker John Harrison around 1722. An escapement, part of every mechanical clock, is the mechanism that causes the clock’s gears to move forward by a fixed distance at regular intervals and also gives the pendulum (or the balance wheel) periodic pushes to keep it swinging.
• Combining simple machines

Complex machines have advantages over simple machines. They often are provide a better solution than just a simple machine alone. These questions step through the Engineering Design Process.

• An escalator is a moving inclined plane. A roller coaster is many steep inclined planes with lots of wheels, pulleys and gears to keep the cars moving. How can a machine move people up a hill?
• Stapler, can opener, wheelbarrow, hand drill, bicycle – all are complex machines. They are made by combining the simple machines. Which simple machines can do some of the work?
• Joining simple machines into complex machines requires planning. Originally, bicycle pedals were connected directly to the wheels. On modern bicycles, the pedals are not connected directly to the wheels.: How can simple machines be combined? How can the work transition from one simple machine to the next?
• 3-D printers are amazing new manufacturing devices that are being used to create complex machines. In many cases, these machines could not have been made with traditional machining tools used in the past.: How do 3-D printers work? How do the 3-D printers know what to make?
• Some times less is better. Some machines are improved by making something less complex. Modern material are stronger, lighter and easier to make into complex shapes. What are some examples of simple machines that are replacing older more complex machines?

That’s engineering

• dynamics

Engineering ideas

• Levers , Pulleys , Wheels , Ramps, Inclined Planes , Wedges , Screws, friction, efficiency, compound machines

Do it
Here are some challenges for you to work on…

• Fantastic contraption (game-based learning, web, free) – build a machine from simple parts to move a goal-object to the goal area of the level. For each level there are many solutions. simple controls and step-by-step tutorial
• play the [[http://www.edheads.org/activities/odd_machine/index.shtml}Compund Machine game]] – Learn how forces and simple machines can work together to create The Compound Machine
• Build a working compound machine incorporating at least 3 different simple machines that will pop a balloon [2]
• design a complex machine to do a task for your home that includes at least 3 simple machines. Check out Rube Goldberg site for more info.
• show each simple machine being used and how it makes the work easier
• design a home or office building that provides handicap access using at least 2 simple machines, why, and how the make life easier.
• evaluate 3 inventions in history that used simple machines. Find information on the inventor
• use paper, popsicle sticks, glue and marbles to create a miniature roller coaster using math and science, how a roller coaster works.
• Goldburger to go – design a machine that serves lunch to the ZOOM cast and crew. They’ve called it the Goldburger To Go, and they need your help to finish it. Requires Flash 6 or later.

Design and conduct an experiment to test these questions

1. Is a weight easier to move when the force arm is longer, shorter, or the same length as the weight arm?
2. What type of screw or nail holds better?
3. What angled ramp will make it easier to pull the book?
4. What type of lever works best to lift an object?