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+ Ship the Chip Sort It Out Pulleys and Force Christopher Lester Yvonne Pelham Moshe Kam D.G. Gorham TISP: Uruguay 9–10 May 2009 User Handout Day 1

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+ Package design and the engineering behind shipping products safely Exercise 1: Ship The Chip

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+ Ship the Chip Design a package that will securely hold a potato chip and protect it from breaking when dropped Construct the lightest package to get the highest score Overall score based on: Weight of the package Volume of the package Intactness Score 3 The Challenge

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+ Ship the Chip 1. Sketch a design on the worksheet Label your worksheet with Table # and Team Name 2. Construct a model of your package 3. At a test station, drop the package from a height of 1.5 meters 4. Open your package and examine the chip 5. Calculate and record your score 6. Using a second kit, redesign and construct a new package Record the second design on the worksheet 7. Label your package with Table # and Team Name 8. Submit your worksheet and package to the Test Team for overnight testing 4 Procedure

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+ Ship the Chip Cardboard – 22 cm x 28 cm 10 Craft sticks 6 Cotton Balls String – 91 cm Plastic wrap – 1 sheet of 22 cm x 28 cm 10 Toothpicks Foil – 1 sheet of 22 cm x 28 cm Paper – 1 sheet of 22 cm x 28 cm 1 Mailing label 1 Potato Chip 5 Materials

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+ Ship the Chip Scissors Pencils/Pens Rulers Digital Scale Marking pen Calculator Clear Adhesive Tape Masking Tape 6 Tools and Accessories

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+ Intactness score : 100: like new, perfect 50 : slightly damaged; cracked but still in one piece 25 : broken in pieces 5 : broken in 6-20 pieces 1 : broken into more than 20 pieces; crumbled 7 Ship the Chip Scoring

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+ Ship the Chip We will imbed the package in the smallest-volume rectangular prism that contains it We will calculate the volume of the prism; Width x Length x Height For example : 3cm x 4cm x12cm =144 cm 3 in the prism shown below If your package weighed 100g and had a volume of 800 cm 3 and the chip has arrived broken in 3 pieces: 8 Calculating Volume

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+ The engineering behind industrial sorting processes Exercise 2: Sort It Out!

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+ Groups of 2 You are a team of engineers hired by a bank to develop a machine to sort coins that are brought in by customers. Must mechanically sort mixed coins into separate containers. In our experiment we use washers: ½ Inch 1 Inch 1¼ Inch 1½ Inch Sort It Out Your Turn 10

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+ Sort It Out How good is it? 1: “Distance” performance index: A washer that does not get sorted has maximum D error = 3 Your Turn ½in 1in 1¼in 1½in 1 Distance from correct bin here, D error = 2 bins ½ ½ ½ ½ ½ 1½ 1¼ ½

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+ Sort It Out How good is it? 2: “Percentage” performance index: Your Turn 12 ½in 1in 1¼in 1½in ½ ½ ½ ½ ½ 1½ 1¼ ½ # of washers incorrectly identified Total # of washers to sort40 5%

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+ Materials: glue, tape, paper or plastic plates, cardboard, scissors or hole punch, foil, paper, cardboard tubes washers Design (draw) a mechanical sorter that can separate the ½in, 1in, 1¼in, 1½in washers Input: either Parallel – all washers are inserted at start of your sorter together; or Serial – washers are inserted at start of your sorter one at a time Output: Each size of washer in its own physical container Sort It Out Your Turn 13

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+ Sort It Out At your table, choose 2 groups to build a parallel sorter; the other 2 groups will build a serial sorter You will have 45 seconds to allow your sorter to operate Predict the value of the two performance indices for your design Construct your sorting mechanism Test it! Can you do better? Your Turn 14

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+ All about force and how pulleys can help reduce it Exercise 3: Pulleys & Force

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+ 16 Fixed PulleyMovable Pulley Pulleys & Force Basics of Pulleys: Two orientations

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+ Pulleys & Force Mechanical Advantage Mechanical Advantage (MA) is the factor by which a mechanism multiplies the force or torque put into it. Ideal MA: Actual MA: 17 This movable pulley system has a mechanical advantage of 2

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+ Work is the amount of energy transferred by a force acting through a distance Work = Force x Distance Work = Force x Distance A bigger mechanical advantage decreases the force required, but increases the distance over which it must be applied The total amount of work required to move the load stays the same 18 Pulleys & Force Work

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+ The ratio between Actual and Ideal mechanical advantage is Efficiency Frictionless system = 100% Efficiency 19 Pulleys & Force Efficiency

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+ Pulleys & Force Measuring Tension Spring Scale Calibrate: Hold spring scale at eye-level and turn adjustment screw until the internal indicator is precisely aligned with the top zero line Measure: Create a loop in the end of the rope you want to measure tension in; attach spring scale to loop. Hold the spring scale steady and read off the tension measurement. 20

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+ Groups of 2 Develop 2 systems to lift a filled soda bottle 10cm with 1 pulley 2 pulleys Build your systems Measure the distance the soda bottle moves and compare it to the distance you had to pull What is the actual mechanical advantage? Measure the force you must exert on the string and compare it to the force that is finally transmitted to the soda bottle What is the ideal mechanical advantage? Calculate the efficiency of each system Pulleys & Force Your Turn 21

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+ Now join with one other group at your table Develop 2 different systems to lift a filled soda bottle 10cm with all 4 pulleys Build both systems What are their actual mechanical advantages? Ideal? Which one has a better efficiency? Why do think that is? Pulleys & Force Your Turn 22

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