minneapolis kids science club training3

A project of the Center for Science Education at EDC Inc,Funded by the National Science Foundation NSF # 0917576

Minneapolis Kids Science Club TrainingMinneapolis, Minnesota

April 29, 2010

Copyright 2008 Education Development Center, Inc.

Challenge #1: Invent a Bridge Make a Bridge over an 8½ inch River using just 4

sheets of paper. Make the bridge as strong as you can. It must not

be taped or fixed to the river banks

MATERIALS• 4 sheets 8½ x 11 paper• “River Banks” (Books or boxes)• Metal Washers• Paper Cup and Cardboard Square• Elastic Bands (just a few)• Tape (just a little)

ROLES• Chief engineer• Materials getter/

presenter • “Spy”/ Data

collector

What do I do?1. Take a sheet of paper and color it to look like a river. Make the water

flow in the direction of the long side of the paper.2. Lay your “river” on the table and place books or small boxes on either

side making river banks. The river banks must be exactly 8-1/2 inches apart.

3. Using only 4 sheets of paper, make a bridge that reaches across the river. The bridge must not be taped or fixed to the riverbanks and not touch the water.

4. Test the strength of the bridge:a. Place the cardboard square in the middle of the bridge.b. Place the drinking cup on the cardboard.c. Begin adding load—washers—until the bridge is just about to collapse.

5. Count how much load is in the cup when the bridge is just about to collapse and record the number next to your team name on the class data sheet.

6. Think about what worked/what didn’t when constructing your bridge, and list your ideas on Data Sheet—Activity 1.

What to think about• Are there some shapes you can make your paper

bridge into that are stronger than others?

• Where is the weakest/strongest part of your bridge?

Introducing the Activity

• Before beginning the activities, have the kids draw their own idea of what a bridge can look like on one or two big sheets of paper and put them on display somewhere where everyone can see them. Ask them if they have ever seen a bridge like the one they have drawn. For each bridge drawing, ask the children:

• What do you think it was built for (road, rail, pedestrian, ect)?• What is it made of (wood, steel, concrete, ect)?• What part of it really makes the bridges stand up?• What were the biggest problems in building each particular

bridge?

Leading the Activity

• Why did you decide to place that piece of paper/tape in that position?

• Does it matter how tight /loose you roll the beams?• Which shapes can you make your paper into that are the

strongest?• Where is the weakest/strongest part of your bridge?

As you talk with the children, ask any of the following questions (or similar questions) to stimulate thinking about how they are designing their bridges.

Leading the discussion• Ask the team members first, then the rest of the group, for their

predictions (how much will it hold?). Have the kids writ their predictions on a piece of paper or notebook.

• Ask both the team members and the group what design features (in their opinion) make this bridge weak or strong?

• Test the bridges by adding load to them.• When you see that the bridge is at its breaking point, stop adding load and

ask for new predictions. Ask where the weakest point of this bridge is.• Add more load until the bridge almost fails but do not completely destroy

the bridges even if the kids want to. It’s better to improve upon an existing design rather than having to start all over after every test. Record the maximum load on the group data chart.

• Ask the kids how close their predictions were to that actual outcome.

Discussion Questions1. What part of the bridge is the strongest?2. How did you change your bridge design to make it stronger?3. If you made tube beams, what was the best shape: round?

square? rectangular? 4. Which is better: loose or tight tube?

• During the discussion, try to draw out the following points. They will be very helpful as you move into Activity 2.

Paper is stronger in the form of a beam rather than a flat sheet or board.

A good shape for a beam is a cylinder (round tube). The tighter the cylinder is rolled, the stronger it seems to

become.

Challenge #2: Rolled Beams Use rolled beams to make a Bridge over an 8½

inch river using just 4 sheets of paper. Use rolled beams to make a Bridge over an 11

inches river using just 6 sheets of paper

MATERIALS• 6 sheets 8½ x 11 paper• “River Banks” (Books or boxes)• Metal Washers, Water Bottles, etc• Paper Cup and Cardboard Square• Elastic bands (just a few)• Tape (just a little)



collector

What do I do?• Make a bridge using tubes

(rolled beams).• When you are ready, test

the strength of the bridge in the usual way.

• Count how much load is in the cup just as the bridge fails, and record the number on the class data sheet.

What to think about• Does it matter how tightly

the tubes are rolled?• What is the best way to

make a long tube (more than 11 inches long)?

• Tubes seem to be stronger than flat paper roadways. Why is that?

Introducing the Activity• Before you begin, spend a few minutes with the kids

discussing the bridges they made in the last session.• Get out the What Works? Chart from the last session and ask

the kids if they have any ideas to add to (or take away from) what is already there.

• Ask how they would go about making their bridges stronger if they could start all over again. Listen to their answers and try to summarize for them what you think are the main opinions and ideas.

• After you summarize the kid’s opinions, tell them that you would like them to use only beams today. Define the term “beam” and use this term often throughout the activities.

• Remind the kids of its meaning as well.

Leading the Activity

• During the activity, walk around to each group every couple of minutes to see how they are doing and to ask questions about their design.

• Try to encourage the team members to explain to each other why they are making or agreeing with certain choices.

• If no obvious questions comes to mind, ask one or more of the three basic questions to get them thinking about what they’re doing.– What works (and what doesn’t)?– What have you tried (and what happened)?– What has worked for other teams?

How to make a tight tube

• Take a sheet of paper and lay it on the table. Place a pencil along one edge of the paper.

• Roll the paper around the pencil until the whole sheet is tightly rolled into a single tube.

• Place a small piece of tape at each end and in the middle to hold the tube in shape, and take out the pencil.

• Use different-sized pencils (or dowels) to roll thinner or fatter tubes. Experiment to see which are strongest.

Leading the discussion

• Have the teams write down a prediction of how much load each bridge will carry.

• Test each bridge and ask the group to explain what features of the bridge made it perform well or poorly.

• Continually remind the teams that if a bridge carries a large load, it is because the bridge is strong, not because the builders were lucky or possess some special talent.

• The basic question to ask is always:– What is it about the way this bridge is built that makes it strong/weak?

Leading the discussion• More specific questions might be:

– Which is stronger: tubes or flat boards (roadways)?– Does it matter how tightly the tubes are rolled?– Where were the weak places on these bridges?

• At the end of the day, ask the kids the following question:– Is there any other way we could use paper that would make a strong

bridge?

• The discussion at the end of the day ought to focus heavily on the questions:– How important is the shape of a beam?– Are some shapes stronger than others?

• Just before they leave for the day, show them the accordion fold. Demonstrate how strong a single sheet of paper becomes when it is folded this way. Tell them that’s the next project.

Challenge #3:Accordion Beams

Part A Use accordion beams to make a Bridge over an

8½ inch river using just 4 sheets of paper.

MATERIALS• 4 sheets 8½ x 11 paper• Metal Washers, Water Bottles,

etc• Paper Cup and Cardboard Square• Elastic bands (just a few)• Tape (not too much)



collector

What do I do?Part A1. Make one or two accordions using single sheets of paper.2. Set up accordion as a bridge across 8-1/2 inch river and test

how strong it is in the usual way.3. Count how many folds there are in each accordion and record

on PART A of Data Sheet—Activity 3 the maximum load just as the bridge fails.

Part B4. Use four sheets of paper to make one accordion bridge over an

11-inch river.5. Count the folds and record the number on part B of Data Sheet

—Activity 3.6. Record how much load it can hold on the data sheet.7. Try different numbers of folds to find out which number holds

the most.

What to think about

• Does the number of folds in your accordion change thestrength?

• What is the best way to join sheets of paper to make a long bridge?

• When an accordion beam fails, what did you see actually happening to the paper?

• How can you make an accordion beam stronger? • Is every team using the same standard for counting folds?

Leading the activity

• When most of the teams have successfully folded and tested six or more accordions with a range of numbers of folds, call the whole group together to review the results and record these results on a class data chart.

• Add any findings you all agree on to the What Works? chart.

• Now give the kids the main challenge for this activity. Ask them what details they might think about (# of folds, joining sheets) as they make their bridges longer and then let them start working.

Part BUse accordion beams to make a Bridge over

an 11 inch river using just 6 sheets of paper.

MATERIALS• 6 sheets 8½ x 11 paper• Metal Washers, Water Bottles,

etc• Paper Cup and Cardboard Square• Elastic bands (just a few)• Tape (not too much)

Challenge #3:Accordion Beams


• After some time, call the groups together for a test-and-tell session. Add any findings you all agree on to the What Works? chart.

• Some questions you could ask are:– What are some important details you should remember when folding

the accordion?– How many folds is best?– Where are the weak places on these bridges?– What is it about tubes and accordions that makes them so strong?


• A question you want to steer clear of:Why are these shapes stronger than the others?

• This often leads to the kinds of forces acting in a beam which is far more than the kids need to (or can) understand at this age.

• Observable fact:– When you stand on a beam, depth (thickness) of a beam is more

important for strength than width.

• Rule of thumb for bridges:– Thicker is stronger than wider

Assessment

• Folding the pleats: Do the kids fold carefully and evenly?• Joining sheets: Do the kids recognize that it is better to join

the sheets before folding?• Using tape: Are they judicious in the use of tape?• Setting up the bridge: Do they place the beams and the load

carefully into position?• Adding load: Do they add load gently and gradually so as to

not weaken the bridge through jolting?• Making design judgments: Do they recognize that making

adjustments to the design of the bridge will improve its strength, and do they actually make such adjustments?

Challenge #4: Columns Make a structure that is 4¼ inches high using

just 4 sheets of paper Test the maximum load this structure can carry

MATERIALS• 4 sheets 8½ x 11 paper• Metal Washers, Water Bottles, etc• Paper Cup and Cardboard Square• Elastic bands (just a few)• Tape (not too much)



collector

What do I do?

• As a team, decide which kind of columns you think are strongest.

• Make your columns.• When ready, place one cardboard square on the table and

carefully place your columns on top of it. Put the second square on top of the columns.

• Place the smallest load (small soda bottle) on the top square. If it holds up, try the medium load (juice box) on top.

• Carefully add heavier and heavier loads (finally try the gallon jug) until your columns crumple or collapse.

• On Data Sheet—Activity 4, write down the greatest load (in ounces of water) that your structure carried.

What to think about

• What is the best shape for paper columns, tight or loose?

• What is the best way to place columns under the load?

• Which is the best direction to roll/fold the paper for this challenge?

Introducing the activity

• Show the kids some pictures of long bridges.• Ask why the columns are there, and what problems they

solve.• Where are the strongest and weakest parts of the bridges in

the pictures?• You notice that some bridges have columns close together

and some far apart while some are short and others are tall, ask if they can come up with any explanations for these differences.

• These are good ways to introduce the activity.

Leading the activityAs the teams work, walk around and ask them why they made various choices, for instance:

– If you choose to make your column round, square, triangular, why did you choose that shape?

– How tightly rolled/folded should the columns be? How do you know this?

– What is the best placement or arrangement for your columns to ensure stability?

Testing the structures1. Place one cardboard square on

the table/floor.2. Place all your columns into your

chosen positions.3. Place the other square on top of

columns.4. Carefully place a load on top of

cardboard, one at a time.5. Record the maximum load( oz.

of water) on team or class data chart.

During testing, you can hold the side of the load to keep it from falling.


Questions:o Does it matter how tightly you roll the tubes? What is best? o Are long tubes better than short ones, or short better than

long?o What is the best shape for the columns (round, square, ect.)?o How can you make sure the structure doesn’t fall over

sideways?o Can you explain how a column is so much stronger than a

beam that looks identical (but is not lying on its side)?

Assessment

• In addition to skills related to bridges, look for more general skills related to how the kids work individually or as large or small groups.

• Taking turns and sharing the hands-on work• Asking each other for help before asking you• Listening when their peers share ideas• Responding constructively to ideas from peers or adults• Making deliberate changes to their designs to improve how

they work• Making changes only one factor at a time• Keeping data and records where appropriate

Questions?

Copyright 2008 Education Development Center, Inc.

NPASS2 website:http://npass2.edc.org

minneapolis kids science club training3

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