LEGO Zipline

[Image of a LEGO zipline and a tray filled with LEGO parts and pieces.]

Objective:1. Design a LEGO zipline carriage that can ride from one end of a zipline to another.2. Transport a LEGO minifigure safely from one end of a zipline to another.3. Use the Engineering Design Process [EDP] of Ask, Imagine, Plan, Create, and Improve to refine the design and improve the result.

Prerequisite Knowledge: Balance Studs not on top [SNOT] LEGO building technique Descriptions of motion [position, velocity, acceleration] Stability

NSTA Science Process Skills: Observe – Students observe their design choices and effects. Measure – Students measure the time of their zipline carriage’s

descent. Sort – Students sort their LEGOs at the end of the experience. Predict – Students predict which design choices will be effective at

moving the carriage. Communicate – Between create and improve steps of the EDP,

students talk about their design and show how well it works. At the end students summarize their changes and results.

Accessibility: (Specific changes to procedure in blue and parentheses) Attach a bell to the carriage so that it makes noise when it reaches the

end of its zip.

Talking stopwatches Create models of the pulley mechanism to show students. Create 2 basic carriage models that are balanced and unbalanced. Use a tactile drawing board for the planning portions.

What You Need: [Lengths are sized assuming an 8’ folding table, longer lengths of twine can be used for more spectacular results.]

LEGO 1030 set – 1 per 2 LEGO minifigure, various types – 1 per 2 Twine, polyethylene, low friction, 10’ – 1 per 8 Ring stands – 2 per 8 Textbooks – 2 per 8 Paper, office – 1 per Pencils – 1 per Stopwatches – 1 per 2 (Bell – 1 per 2) (Tape, scotch, roll – 1 per 2) (EiE Design Cycle, tactile graphic – 1 per 2)

[Four various bracket placement images]

Setup 1 zipline for every four pairs of students. This can be done on an 8’ table, though larger ziplines are more spectacular. Consider your space and set the ziplines up in places where students will not walk in to the lines. One set of brackets has wing nut and bolt to [minimally] adjust tension. Brackets can also be mounted upside down, in order to give more angle options. Brackets can be mounted along a single table, or across a span to allow more clearance.

1. Set two ring stands at opposite ends of the table. 2. Place a text book or other heavy weight on the support for the ring stand.3. Tie the twine to both ring stands. On one ring stand tie the twine as close to the top as possible with a secure knot. On the other, tie the twine about 6” from the top of the textbook securely.4. Move the ring stands apart until the rope is under tension and ruler straight.- Build one obviously unbalanced zipline carriage. Test it on the line to be sure it will fall.- Put the LEGO 1030 sets in some central location.Optional:

- Preload a video [https://www.youtube.com/watch?v=LQusBAhL-Gs] to show footage of the real life application of ziplines and 1st person footage of the ride. Source: BBC Worldwide. Length: 2:58 (Add audio description to this video using YouDescribe (http://youdescribe.org/search.php), a free crowd-sourced description tool for retrofitting inaccessible videos.)

What You Do:

Introduction:1. Ask, “Have any of you been on a zipline before?” 2. Tell, “Ziplines are a great way of traveling over difficult terrain like a jungle, river, or swamp. They use gravity to quickly move someone from one side to another. When they are done, the carriage can be pulled back to the starting part.”3. Optional: Show students the video of ziplines over the Nu Jiang River.4. Explain, “We are going to create a LEGO model of a zipline carriage that can carry a minifigure across our zipline.”5. Ask these questions about the model:

a. “How is our model like the real thing?” [Works on gravity; carries things across the line.]

b. “How is our model not like the real thing?” [Made of LEGOs, different rope, smaller, etc.]6. Explain, “Sometimes scientists use models instead of the real thing to practice on. If the real thing is too big, small, far away, dangerous, or changing too quickly or too slowly, scientists use a model to learn how it works.”7. Ask, “Would any of you be willing to test out a brand new zipline carriage that runs 500 feet over a rushing river?” [No.]

Explain the Mechanism:1. Show students the basic mechanism for going across. Tell, “The pulley runs along the line. It is connected to an arm of LEGOs that is pinned together.”

[Image of a LEGO piece traveling down a zipline]2. Assemble the basic mechanism pictured above and send it down the line. It is a pulley attached by a pulley pin to a first hole of 1x6 Technic brick from the side. The last 2 holes of the 1x6 Technic brick have pins in them and are attached sidewise to the 1st 2 holes of a 1x8 Technic brick. (Pass around the pulley mechanism models for students to observe.) (Attach the bell to the model.)3. Attach the unbalanced carriage that you built earlier to the line. Send it down the line. The result will be catastrophic. (Pass around the balanced and unbalanced models to students at this time. Ask clarifying questions (e.g. Describe each model. What is the same? What is different? Do they stand up on their own?). (Attach the bell to the model.))4. Ask, “What did my model do?” [Fell off the line.] “Why did my model do that?” [It was unbalanced.]5. Ask, “What are some ways we could make our zipline more stable?” (Answers will vary.) Record answers on the board. (Verbalize what you are writing. Encourage students to make a list for their own notes).

Activity:1. Introduce the challenge, “Your jobs are: 1) to design a zipline carriage that can carry a LEGO minifigure across the line without falling off, 2) carry the weighted brick and the LEGO minfigure across the line without falling off.”2. Ask, “What questions do you have about this challenge?” [Questions will vary.] Record the questions on the board and encourage students to ask many and elaborate on them. The following are the actual constraints; however, others may exist or be fun to try:

a. The LEGO minifigure can’t be attached to the zipline carriage in any way [i.e. feet can’t be in studs.]

b. Students can only use the parts in the 1030 set.

c. Students can’t give the minifigure a push when launching them, gravity only.

Introduce the EDP. Draw the steps of Ask, Imagine, Plan, Create, and Improve on the board.

[An engineering design process image from Engineering is Elementary curricula. 5 steps in a cycle: Ask, Imagine, Plan, Create, Improve]

1. Explain each step briefly then ask, “Which step have we done already? [Ask]2. Tell, “Next we will imagine our design and draw it out. I want each person to draw two designs for how we could build our zipline carriage. Please be silent during this portion, it helps some people think.”3. Group students into pairs by some expedient means. Pass out the writing utensils (tactile drawing boards) and direct students to begin. If a student is having trouble coming up with more than one idea tell them that the 2nd idea doesn’t have to be completely different than the first, it can be the first idea plus something else.4. Direct students to share their ideas and generate a plan together. Say, “The best ideas are usually a few ideas jammed together into one plan. Try to include parts of both people’s plan. Your plan must be drawn and labeled with its parts. You must both agree on the plan. When you come to see me in the LEGO line the first question I will ask is, ‘Do you agree?’, if both people don’t say yes, then you go back to your table until you agree.”5. If disagreements persist direct students to play rock-paper-scissors to settle their disagreement. Good ideas can also stay “on the drawing board” for the improve step.6. As students finish their plans, stop the class and explain the roles.

a. Parts manager – hands parts to the builder, tests the zipline for balance, tests the final product, suggests ways to put LEGOs together, but doesn’t touch.

b. Builder – Puts the LEGOs together, has final say on design elements, and uses the stopwatch during testing.- These roles can switch back and forth every 5 minutes for younger students and every 10 minutes for older students. Assign who starts as builder and parts manager.7. As students finish their plans, ask if they agree, then hand them their LEGO 1030 sets (with bells and tape). As students work on their creations, be sure they follow their roles. If roles are working, ask students about their design choices and why they made them, but offer no opinion on whether they will work. Instead, offer students a chance to balance their zipline carriage on the line, if balanced, they can give it a test.8. Pass out the stopwatches. Tell, “We are looking for the fastest and the slowest ride that gets the rider to the bottom safely. Use these stopwatches (talking stopwatches or stopwatch mobile app) to time how long it takes to go to the other side.”9. After most students have built their plan [~20 minutes], stop the class. Tell, “Now we are going to test them. Before you test I will ask you what the name of your carriage is, why you built it that way, and to hold it up (or pass it around, carefully) so people can see.”10. Conduct the tests with each group. (Pass the design around carefully.) Time each descent and direct the group to write it down on their plan paper. If students have built these elements, point them out:

a. Carriage connects by 2 pulleys rather than one. b. Carriage contains a box for the minifigure.c. Carriage is larger on the bottom or weighted.d. Carriage has a stopping bumper or other feature.e. Carriage moves slowly down the line. f. Connection to the pulley is reinforced.

11. After testing, ask students, “What was the same about the carriages that made it down the line safely?” Record these design elements on the board with the others from earlier. Add phrases to your list from before that students repeat (and verbalize as you write).12. Direct students to improve their design. Say, “Engineers test things out more than once to build ziplines better and better. We are going to be engineers and try to build these ziplines better.”

13. Direct students to draw their new design or record the improvements they would like to try on the back of the page (or on tactile drawing board). If students are having trouble making improvements refer to the list on the board.14. Continue switching the builder and parts manager roles as before. Students may test their design and make several improvement cycles during this time [~20 minutes.]15. Tell, “Now we are going to test again. When it is your turn tell us:

a. Whether you are going for the fastest time or slowest time.b. What time you got last time.c. What changes you made to your design. d. The name of the design.

16. Conduct the tests with each group. (Begin by passing the design around.) Time each descent and direct the group to write it down on their plan paper. Emphasize the success of any of the improvements listed. After each test ask, “Did they improve?” Note: Direct all students to use the stopwatches on each trial. The duplication guarantees correct stopwatch use and improves attention.17. Direct students to take apart and put away their LEGOs. The builder takes the design apart and the parts manager puts the pieces away.

Reflection:1. Reinforce the design cycle. Ask students, “When did we do the Ask

step?”, “When did we do the Imagine step?” and so on.2. Say, “Raise your hand if you improved your design.”3. Ask, “Which step was the easiest step? Why?”4. Ask, “Which step was the hardest step? Why?”5. Tell, “Engineers start solving a problem by making models and testing

them out just like we did. It gives them a chance to make sure an idea will work before building it out of full size materials. Now that we have tested our models, would you try to zipline on a model like the one you built?”

Student Questions:1. What did you do during the Ask step?2. What did you do during the Imagine step?3. What did you do during the Plan step?4. What did you do during the Create step?5. What did you do during the Improve step?

6. Which step was the hardest? Why?7. Which step was the easiest? Why?8. Would you ride your zipline design? Why or why not?9. If you could improve your design one more time, what would you try?

Differentiations and Accommodations:1. Increase the height of the zipline. This makes it easier for young students

to time with stopwatches and increases the likelihood that all designs will move. It increases the difficulty of both challenges.

2. Add motors. A pulley attached to a motor can be used to propel the carriage across a level zipline. Without gears the motor will spin the pulley too quickly. By attaching a small gear to the motor and a larger pulley to the zipline the carriage can move on its own. The motor changes the weight distribution of the carriage and requires improved balance. Further, the motors can be used to make the carriage go up the zipline.

3. Add weight. Require students to transport the weighted brick (pig if using the video) and the minifigure. This will require students to build their designs with different balance and symmetry.

4. Add improve cycles. Engineers typically improve a design until it reaches some predetermined criteria. Decide on some threshold amount of time to go over if trying for a slow ride or under if trying for a fast ride that is reachable by students. This time differs greatly by zipline setup. For the setup described 10 seconds or over and 4 seconds or under are about the correct level of difficulty.

5. Add design criteria. Engineers design with carefully written criteria called specifications [e.g. the box must be enclosed, the design must function in the wind [fan blowing across], the design can’t go over a certain weight, or the design can only use a certain number of pieces [cost]]. These limitations can increase the amount of imagination and creativity necessary to achieve the goal.

Next Generation Science Standards Alignment:2-PS1-3; K-2-ETS1-1; K-2-ETS1-2; K-2-ETS1-3; 3-PS2-1; 4-PS3-1; 4-PS3-4; 3-5-ETS1-2; 3-5ETS1-3; MS-ETS1-2; MS-ETS1-3;

CCC Standards Alignment:W.2.7; W.2.8; RI.2.1; MP.5; W.3.7; W.4.7; W.4.8; W.5.7; WHST.6-8.7