In this lesson, students learn about work as defined by physical science and see that work is made easier through the use of simple machines. Already encountering simple machines everyday, students will be alerted to their widespread uses in everyday life. This lesson serves as the starting point for the Simple Machines Unit.
To display the results from the previous activity, each student designs and constructs a mobile that contains a duplicate of his or her original box, the new cube-shaped box of the same volume, the scraps that are left over from the original box, and pertinent calculations of the volumes and surface areas involved. They problem solve and apply their understanding of see-saws and lever systems to create balanced mobiles.
Simple machines are devices with few or no moving parts that make work easier. Students are introduced to the six types of simple machines the wedge, wheel and axle, lever, inclined plane, screw, and pulley in the context of the construction of a pyramid, gaining high-level insights into tools that have been used since ancient times and are still in use today. In two hands-on activities, students begin their own pyramid design by performing materials calculations, and evaluating and selecting a construction site. The six simple machines are examined in more depth in subsequent lessons in this unit.
Simple machines are devices with few or no moving parts that make work easier, and which people have used to provide mechanical advantage for thousands of years. Students learn about the wedge, wheel and axle, lever, inclined plane, screw and pulley in the context of the construction of a pyramid, gaining insights into tools that have been used since ancient times and are still important today. Through numerous hands-on activities, students imagine themselves as ancient engineers building a pyramid. Student teams evaluate and select a construction site, design a pyramid, perform materials calculations, test a variety of cutting wedges on different materials, design a small-scale cart/lever transport system to convey building materials, experiment with the angle of inclination and pull force on an inclined plane, see how a pulley can change the direction of force, and learn the differences between fixed, movable and combined pulleys. While learning the steps of the engineering design process, students practice teamwork, creativity and problem solving.
Being able to recognize a problem and design a potential solution is the first step in the development of new and useful products. In this activity, students create devices to get "that pesky itch in the center of your back." Once the idea is thought through, students produce design schematics (sketches). They are given a variety of everyday materials and recyclables, from which they prototype their back-scratching devices.
This lesson introduces students to three of the six simple machines used by many engineers: the lever, the pulley, and the wheel-and-axle. In general, engineers use the lever to magnify the force applied to an object, the pulley to lift heavy loads over a vertical path, and the wheel-and-axle to magnify the torque applied to an object. The mechanical advantage of these machines helps determine their ability to make work easier or make work faster.
In this activity, students reinforce their understanding of compound machines by building a catapult. This compound machine consists of a lever and a wheel-and-axel. Catapults have been designed by engineers for a variety of purposes from lifting boulders into the air for warfare to human beings for entertainment; the projectiles in this activity are grapes for a magic act. Given the building materials, students design and build their catapult to launch a grape a certain distance.
Students investigate the ways in which ancient technologies six types of simple machines and combinations are used to construct modern buildings. As they work together to solve a design problem (designing and building a modern structure), they brainstorm ideas, decide on a design, and submit it to a design review before acquiring materials to create it (in this case, a mural depicting it). Emphasis is placed on cooperative, creative teamwork and the steps of the engineering design process.
Students expand upon their understanding of simple machines with an introduction to compound machines. A compound machine a combination of two or more simple machines can affect work more than its individual components. Engineers who design compound machines aim to benefit society by lessening the amount of work that people exert for even common household tasks. This lesson encourages students to critically think about machine inventions and their role in our lives.
Through a five-lesson series with five activities, students are introduced to six simple machines inclined plane, wedge, screw, lever, pulley, wheel-and-axle as well as compound machines, which are combinations of two or more simple machines. Once students understand about work (work = force x distance), they become familiar with the machines' mechanical advantages, and see how they make work easier. Through an introduction to compound machines, students begin to think critically about machine inventions and their pervasive roles in our lives. After learning about Rube Goldberg contraptions absurd inventions that complete simple tasks in complicated ways they evaluate the importance and usefulness of the many machines around them. Through the hands-on activities, students draw designs for contraptions that could move a circus elephant into a rail car, create a construction site ramp design by measuring different inclined planes and calculating the ideal vs. actual mechanical advantage of each, compare the theoretical and actual mechanical advantages of different pulley systems conceived to save a whale, build and test grape catapults made with popsicle sticks and rubber bands, and follow the steps of the engineering design process to design and build Rube Goldberg machines.
Students apply the mechanical advantages and problem-solving capabilities of six types of simple machines (wedge, wheel and axle, lever, inclined plane, screw, pulley) as they discuss modern structures in the spirit of the engineers and builders of the great pyramids. While learning the steps of the engineering design process, students practice teamwork, creativity and problem solving.
In this activity, students are challenged to design a contraption using simple machines to move a circus elephant into a rail car. After students consider their audience and constraints, they work in groups to brainstorm ideas and select one concept to communicate to the class.
Refreshed with an understanding of the six simple machines; screw, wedge, pully, incline plane, wheel and axle, and lever, student groups receive materials and an allotted amount of time to act as mechanical engineers to design and create machines that can complete specified tasks. For the competition, they choose from pre-determined goal options such as: 1) dumping goldfish into a bowl, 2) popping a balloon, or 3) dropping mint candies into soda pop (creating a fizzy reaction). Students demonstrate their functioning contraptions to the class, earning points for using all six simple machines, successful transitions from one chain reaction to the next, and completion of the end goal.
In this activity, students explore how trebuchets were used during the Middle Ages to launch projectiles over or through castle walls as well as how they are used today in events such as Punkin’ Chunkin’. Students work as teams of engineers and research how to design and build their own trebuchets from scratch while following a select number of constraints. They test their trebuchets, evaluate their results through several quantitative analyses, and present their results and design process to the class.
In this open-ended design activity, students use everyday materials milk cartons, water bottles, pencils, straws, candy to build small-scale transportation devices. They incorporate the use two simple machines a wheel and axle, and a lever into their designs. Student pairs choose their materials and engineer solutions suitable to convey pyramid-building materials (small blocks of clay). They race their carts/trucks, measuring distance, time and weight; and then calculate speed.