Design Machines. Time Part 1: 90 minutes; Part 2: 60 minutes Grouping Small groups. machines

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1 Purpose To design, create, and use simple and complex machines to accomplish tasks. Process Skills Design, predict, observe, measure, collect data, interpret data, communicate, identify and control variables, draw conclusions machines Design Machines Materials (per group) q Data Sheets 1 and 2 q 12 strips of tagboard (or card stock) q 12 empty rolls of toilet paper q scissors q yarn q roll of tape (masking or clear) q lightweight ball q meter stick Background In science, work is what happens when a force moves an object from one place to another. A machine is a tool that lets us do work faster, easier, and often more safely. A simple machine is a machine with few or no moving parts. Scientists identify several kinds of simple Simple Machines machines: the inclined plane, the screw, the wedge, the lever, the wheel and axle, and the pulley. (The gear is sometimes considered to be another simple machine, inclined plane screw but it will not be used in this activity.) A complex machine is made up of two or more simple machines. Each simple or complex machine is designed to help people perform a certain task. wedge lever Time Part 1: 90 minutes; Part 2: 60 minutes Grouping Small groups wheel and axle pulley Learning A Z 1 Learning A Z All rights reserved.

2 Procedure Part 1: Build and Test Simple Machines 1. As a group, discuss what you know about each of the six kinds of simple machines. Refer to the nonfiction book Simple and Complex Machines for review, if necessary. 2. As a group, think about how you can use the available materials to build each of the six kinds of simple machines. The materials you have been given should be enough to create all six simple machines, so use your resources wisely. 3. Begin constructing one simple machine at a time (see Figure A for examples). Once your group has built all six machines, you will try a challenge that involves making a ball move by using three of your machines. Keep the challenge in mind as you build each machine. Follow these directions as your group builds each machine: Machines Design Machines Inclined Plane: Design and build an inclined plane that will allow the ball to travel down it without any push from you. Wedge: Design and build a wedge that will move the ball by using only a gentle push at the beginning. Lever: Design and build a lever that will move the ball by using only a gentle push or pull at the beginning. Wheel and Axle: Design and build a wheel with an axle that will move the ball by using only a gentle push at the beginning. Pulley: Design and build a pulley that will move the ball by using only a gentle pull at the beginning. Screw: Design and build a screw that will allow the ball to travel down it without any push from you. 2 Learning A Z All rights reserved.

3 4. Draw a picture of each of your simple machines on Data Sheet 1 and list the materials you used to build it. 5. Once your group has designed and built all six machines, test each one by itself. Make sure that it can move the ball according to the directions in step 3. Measure the distance each machine moved your ball by tracing its path with the yarn. Then measure the length of the yarn with the meter stick. Record this data on Data Sheet 1 for each machine. Machines Design Machines 6. Make changes to any machines that do not work as intended, while still following the rules in step 3. Some machines will work better than others at moving the ball. 7. On Data Sheet 1, draw a picture of each of the simple machines your group built. Also, record the materials that you used to build each one. 8. Using Data Sheet 1, discuss with your group which of your simple machines moved the ball the greatest distance. Sample designs These pictures show just one possible way to design each simple machine. Create your own designs as a group. inclined plane wedge lever Figure A wheel and axle pulley screw Learning A Z 3 Learning A Z All rights reserved.

4 Machines Design Machines Part 2: Build and Test a Complex Machine 1. With your group, discuss how to construct a complex machine. Make any three of your simple machines work together to move the ball through a course chosen by your teacher. Do not start building yet! For now, just discuss your ideas for the design (see Figure B for an example). Be sure to consider each group member s ideas. Read these rules and tips to help with your planning: Rules and Tips Find out from your teacher whether you will be asked to make the ball travel far, go fast, go around corners, hit a target, change between levels, or move in some other way. This information will help you design your complex machine. Review the distance results from Data Sheet 1. If you need your ball to travel far, use these results to help you decide which simple machines to use in your complex machine. The simple machines may be connected to one another, or there may be gaps between them so that one machine sends the ball to the next one. if the ball starts at or reaches a wedge, lever, wheel and axle, or pulley, you may give it a gentle boost, but the machine, not you, should do most of the work. If the ball starts at or reaches an inclined plane or a screw, you may set the ball on the machine, but do no push or pull it. Jupiterimages Corp. Learning A Z Figure B 4 Learning A Z All rights reserved.

5 2. Draw the starting design for your complex machine on Data Sheet 2. Also, list the three kinds of simple machines that make up your complex machine. This design is just a plan to help you get started; your plans may change once you actually begin building. 3. Using your group s design plan, assemble your complex machine. Remember, it is okay to change your complex machine from the starting design if needed. Machines Design Machines 5. When your teacher announces that it is your group s turn, follow the rules and tips for using the machines and conduct the test! Your teacher may allow you to make several attempts, including a chance to change your machine between attempts. When all testing is done, you will be asked to reflect on the activity. 4. Once you have built your complex machine, test it out to make sure it works as you had hoped. Continue to make any needed changes or improvements, but only use the materials provided and only use three kinds of simple machines. Once you have changed it for the last time, draw your final design on Data Sheet 2. Learning A Z All rights reserved. 5

6 Machines Design Machines Data Sheet 1 Name Date Collect Data Part 1: Build and Test Simple Machines Inclined plane Wedge Lever Materials used: Materials used: Materials used: Distance: cm Distance: cm Distance: cm Wheel and Axle Pulley Screw Materials used: Materials used: Materials used: Distance: cm Distance: cm Distance: cm 6 Learning A Z All rights reserved.

7 Machines Design Machines Data Sheet 2 Name Date Collect Data Part 2: Build and Test a Complex Machine Starting Design Final Design Which three kinds of simple machines did you use to design your complex machine? How will your complex machine move the ball through the course? Learning A Z All rights reserved. 7

8 Machines Design Machines Questions Name Date Analyze Data 1. In Part 1, which simple machine moved the ball the greatest distance? Why do you think this one worked best? 2. Did your design plan need to be changed once you started building your complex machine? If so, why did it need to be changed? If not, why not? 3. Why did some simple machines require you to provide more force than others did? 8 Learning A Z All rights reserved.

9 Machines Design Machines Questions Name Date 4. Some groups may have used more or less force than your group to move their ball. How would you change the activity to be sure that every group uses an equal amount of force? 5. Suppose you could redesign your complex machine by replacing one of its simple machines with another. Which simple machine would you remove, and which one would you use instead? Why? Draw Conclusions 1. In your own words, explain how a complex machine works. 2. Which kinds of simple machines seem more useful than others at moving a ball? Why do you think this is so? 9 Learning A Z All rights reserved.

10 Teaching Tips machines Design Machines These process activities will provide students with opportunities to increase their familiarity with simple machines the inclined plane, screw, wedge, lever, wheel and axle, pulley, and gear. Students will discover the properties of each simple machine and identify which machine is best suited to complete various tasks. They will also combine simple machines into complex machines. Students may come to appreciate how machines help people accomplish work faster, more easily, and more safely. Set-up and procedures Refer students to pictures from this unit s nonfiction book (and elsewhere) as they design their simple and complex machines. Students may use inquiry to design each simple and complex machine however they feel it will work best. They should be encouraged to modify their designs as they test each machine. See page 3 for possible techniques to assemble each simple machine. These suggested techniques should only be shared with students if they need help getting started. Be sure students use each simple machine as intended. For example, students should not use their wheel and axle or inclined plane as a lever by flicking the ball with either of them. Have students label each simple machine they construct with its type. Some of the simple machines that students assemble may not work as well as students had hoped. But students should still be able to complete each section of Data Sheet 1 for each machine. If the ball did not move at all, they may write a zero in the distance space. For Part 1, have the whole class follow the same course so that the primary variable will be the design of each group s complex machine. The simplest challenge is to measure the total distance each group s ball travels. Other possibilities include testing how quickly the ball reaches a given point, making the ball go around corners and/or change levels, and trying to hit a specific target. Just as students may need to alter their machine designs, you may want to model being flexible with the course design to suit the machines that students built. For Part 2, it may also be best to assign a challenge or course that all groups can try in their own area, rather than using one centralized course requiring groups to move their complex machines from their work area. Some machines may be fragile and could become damaged in transit. Reinforce vocabulary (e.g., work, force, load, simple machine, complex machine, inclined plane, screw, wedge, lever, wheel and axle, pulley) throughout the lesson. It may be helpful to review the nonfiction book Simple and Complex Machines before beginning the exploration. Learning A Z All rights reserved. 1

11 Machines Design Machines MATERIALS extensions and variations Ask students to begin donating clean, empty toilet paper rolls several weeks in advance of the exploration. It may also be helpful to put a collection box in the staff room. Paper towel tubes may be used instead, or in addition. Tagboard and card stock (as used in sentence strips in the primary grades) are strong yet flexible types of paper. Old file folders can be cut into sheets and used instead. Substitute or add materials freely. In each part of the exploration, have students use a Ping Pong ball, a tiny toy car, or another lightweight object that rolls. Because building the simple and complex machines involves some trial and error, have extra materials on hand in case students need to start over. Rather than measuring distances with string and then measuring the string against a meter stick, let students use tape measures if available. Inquiry Science: After students have assembled a complex machine using three of their simple machines, challenge them to create a new complex machine that incorporates more than three types of simple machines. For a longer-term project, students can even design a very complex machine, such as a Rube Goldberg machine, to move their ball in many ways. Variation: Rather than having all groups design machines to follow the same course, have groups each design and build a complex machine that is tailored for a different course or challenge. Then discuss why each group designed its machine as it did. Inquiry Science: Have students use a marble or another object in place of the ball to test their simple and complex machines. Allow them to compare the distances traveled. Did the new object travel farther or differently than the ball did? Why? Math: Create a class graph of the distances the ball traveled using each simple machine. Alternatively, create a graph showing the popularity of the simple machines that groups used in creating their complex machines. Art: Have students cut out pictures from magazines of each type of simple machine they see, and create a classroom bulletin board or collage. Writing: Have students write an acrostic poem about one simple machine. Technology: Have students create a digital slideshow about machines. If a digital camera is available, students can photograph their simple and complex machines and include these pictures in their slideshow. Research: See Using the Internet in the Unit Guide for suggested websites to extend the learning. Learning A Z All rights reserved. 2

12 Machines Design Machines Possible Techniques to Assemble Each Simple Machine Inclined plane: Use one whole toilet paper roll, slice another one in half lengthwise, and slice the remaining half in half again, yielding ramp supports of three different heights. Tape the whole roll, half roll, and quarter roll to the floor with the curved sides up, and space them appropriately to build an inclined plane. Tape a sheet of tagboard atop the toilet paper rolls to create a ramp. The bottom of the tagboard may be taped to the floor, and its side edges may be folded up to keep the ball rolling straight ahead. (For a steeper ramp, cut toilet paper rolls in the opposite direction, making diagonal cuts so the ramp can be attached to the sloped tops of the sliced toilet paper rolls.) Screw: Stand a toilet paper roll upright. Cut the tagboard into small strips, about 3 x 8 cm each. Fold down a 1-cm tab on one side of each of these strips. Starting at the bottom of the toilet paper roll, tape the tab of the first piece of paper so that it follows the seam of the toilet paper roll (diagonally). Place the next strip of tagboard higher on the seam so that it overlaps the first, and tape down the tag against the toilet paper roll. Continue attaching tagboard strips all the way up the seam of the toilet paper roll. Use generous amounts of tape to connect the strips together and to attach them to the tube. Fold up the outer edge of each strip to keep the ball on the track as it coasts down the screw. Students may add to the screw s height by connecting additional toilet paper rolls. Wedge: Crease one side of the toilet paper roll and tape it together. The creased edge will serve as the wedge, and the opposite side will serve as the handle. Alternatively, use a sheet of tagboard folded one or more times as a wedge. Wheel and axle: Roll a sheet of tagboard into a firm rod and tape it in place. Insert this rod through a toilet paper roll to serve as an axle. Alternatively, cut a sheet of tagboard into a nearperfect circle. Then punch a hole in the center of this circle and insert and attach the axle. To demonstrate simple machines, students should only connect a single wheel to a single axle. Lever: Fold a sheet of tagboard into a narrow strip (shaped like a ruler) and tape it together to create a beam, or arm. Use tape to attach it to the top of a toilet paper roll, which will serve as the fulcrum. To propel the ball along the ground, attach the toilet paper roll to the ground in an upright position, with the beam near the ground, so that a flick of the beam will propel the ball in the desired direction. Pulley: Build a simple sled made of folded and taped tagboard. Leave one side of the sled open so that the ball will exit the sled once launched. Tie the sled to one end of a length of yarn. Tape a toilet paper roll to the floor in an upright position. Run the length of yarn around the roll, with the ball and sled on one side and the untethered end of the yarn on the other. Pulling on the untethered end should propel the sled forward and release the ball through the open part of the sled. Gear: This simple machine was not selected for use in this Process Activity because of its complexity of use (most gears do not work in isolation), but it can be added to the exploration if desired. Students can cut out a circle of tagboard and then cut teeth into the edge, or cut teeth into the end of a toilet paper roll. Learning A Z All rights reserved. 3

13 Answer key Machines Design Machines Data Sheets Data Sheet 1: Drawings, materials, and distances will vary, depending on each group s design. Data Sheet 2: Groups should draw their starting and final designs in the appropriate boxes. Three different simple machine types should be listed, and a clear description of how the complex machine will work should be provided. Ensure that the final design follows the procedures, demonstrates an understanding of how each simple machine works, and suits the challenge. EXPLORATION Machines Design Machines Data Sheet 1 Name Date Collect Data Part 1: Build and Test Simple Machines Inclined plane Wedge Lever EXPLORATION Machines Design Machines Data Sheet 2 Name Date Collect Data Part 2: Build and Test a Complex Machine Starting Design Final Design Materials used: Materials used: Materials used: Distance: cm Distance: cm Distance: cm Wheel and Axle Pulley Screw Which three kinds of simple machines did you use to design your complex machine? Materials used: Materials used: Materials used: Distance: cm Distance: cm Distance: cm How will your complex machine move the ball through the course? Learning A Z All rights reserved. Learning A Z All rights reserved. 4 Learning A Z All rights reserved. 4

14 Answer key and explanations Machines Design Machines Questions Analyze Data 1. In Part 1, which simple machine moved the ball the greatest distance? Why do you think this one worked best? Results will vary. The simple machine that allows the ball to travel the greatest distance may be the inclined plane. This simple machine has little added friction, aims the ball in a straight line, and uses gravity for speed. The lever, pulley, or any other machine may propel the ball farther yet, depending on how much force students apply to each machine. 2. Did your design plan need to be changed once you started building your complex machine? If so, why did it need to be changed? If not, why not? Design plans will likely need to be changed once students begin construction. Students may find that a machine falls apart, doesn t work as intended, or can be modified to work better. Flexibility and ingenuity are important attributes for engineers and designers of all types. If students did not change their design, they should explain why they didn t feel it was necessary to do so. 3. Why did some simple machines require you to provide more force than others did? Results will vary. Since the amount of force was not standardized in the procedures, students might use more force with one machine than with another. Some machines, such as the screw and inclined plane, use gravity to move the ball, so students may think these machines did not require any force at all to use. However, lifting the ball to a starting height did require force. 4. Some groups may have used more or less force than your group to move their ball. How would you change the activity to be sure that every group uses an equal amount of force? Responses will vary. Standardizing the use of the inclined plane and screw would likely be easiest; students could be required to construct these machines according to a specific design and use exactly the same technique to release the ball, letting the constant of gravity do the rest. For each of the other machines, rules would have to be added to define how far to flick the lever, how hard to push the wedge, how long a piece of yarn to use in the pulley, and so on. Other materials might have to be introduced, such as a swinging hammer that drives the wedge or a rubber band stretched to a given length that moves the wheel and axle. 5. Suppose you could redesign your complex machine by replacing one of its simple machines with another. Which simple machine would you remove, and which one would you use instead? Why? Answers will vary, depending on the success of student results. Students should opt to replace the least effective simple machine with one that seems more likely to help accomplish the challenge. Learning A Z All rights reserved. 5

15 Answer key and explanations Machines Design Machines Questions Draw Conclusions 1. In your own words, explain how a complex machine works. A complex machine works by combining two or more simple machines into a new machine that makes things move. Complex machines help make work easier, faster, and/or safer. 2. Which kinds of simple machines seem more useful than others at moving a ball? Why do you think this is so? Responses will vary but should be a reflection of each group s results from the exploration. Some simple machines may be more useful in accomplishing one task than another. For example, if speed was the goal, the wedge or lever may have been best. If changing levels was the goal, an inclined plane may have been ideal. And the pulley or screw may have been most useful in making the ball change directions. Additionally, some simple machines may be more useful when used as part of a complex machine rather than in isolation. For example, if groups could have combined four wheels and two axles, they could have built a vehicle to carry the ball far, but one wheel with one axle may not have been very effective. Learning A Z All rights reserved. 6