Problem Based Learning

The Sunset Swing Company

The Best Seat in the House!

• You and your design team have made some of the greatest swings in the country. Your sales team can’t keep up with the orders!

• But recently you have received a number of complaints that your swings aren’t living up to their reputation….

• They are not swinging smoothly and one side of the swing in swinging differently than the other??

• It is time for your engineering and design team to swing into action and determine if it is a design problem or installation issue.

You decide to investigate and analyze one of the cases.

You recently received a letter from a 12 year old girl who lives in Silverdale, Washington. She recently purchased one of your newest swings, The Sunset Surprise. It is one of the fastest selling swings in your new

line!She claims the swing doesn’t work and wants

a refund immediately.Here is her letter……

Dear Sunset Swing Company,

I recently purchased a Sunset Surprise Swing for my birthday and it was a

huge disappointment! I followed all of the directions ( I even reread them 20 times

to see if I made a mistake!) and it doesn’t swing as advertised! I found a tree branch

and tied both swing ropes securely and made sure that the seat was even. I had to

shorten one of the ropes because the branch wasn’t straight. I hopped on and my

sister gave me a push and the swing started to swing unevenly-one side was

swinging differently than the other side. My sister, who is a lot smaller than I am,

tried it and got the same results. I even tried my mom, who is twice my size, and

still one side was swinging differently than the other. We even tried it without a

starting push…same results. I really would like A COMPLETE refund and hopefully

your swing engineers can figure out what is wrong with this swing design. I bought

your swing because of the company’s reputation but now I’m not sure I made a wise

decision. I have enclosed a diagram of the set-up of my swing.

Sincerely;Suzy Swingsalot

Length of rope: 215 cm

Length of rope: 185 cm

Seat is level!

Seat is 75 cm off the ground

Tree limb is at a 45° angle

Design Team Mission:

• Analyze the Problem & Define a Problem Statement

• Identify what you need to know• Gather information and data that will help to

solve your problem• Share your information

• Generate Possible Solutions• Present the solution

Step 1: Analyze the problem and Define a Problem statement

• Analyze the diagram and the letter for factors that may lead to the problem:

• Examples:

– The swing does not swing evenly– They tried 3 different people: Suzy, her little sister, & her mom– The 2 side of the swing are different lengths: 185 cm & 215

cm– The seat of the swing is even and is 75 cm off the ground– Tried it with different “Starting Points” –1 with push other

without

Write a problem statement:• What factor(S) are affecting the Sunset Surprise Swing

that are causing it to swing unevenly?• As all good design team members know, it is important to

develop a model to help investigate how something works or behaves in the real world

• One of your design team suggested that the swing is like a pendulum (* a pendulum is a mass that swings back and forth on a string) & we should model how a pendulum moves to help us with figure out why are swing is behaving “badly”

• Model: A simplified representation of a system. Models are useful for studying systems that are too big, too small, or too dangerous to study directly.

Identify What We Need to Know?

– How can we model a pendulum?– What variables could affect the way a pendulum

swings?– What will we need to do so that we model and

test only 1 variable at a time so we can be sure that is what is affecting our swing’s motion.

Science Vocabulary

• A mass hanging from a fixed point that is free to swing to and fro is called a pendulum

• A cycle is any motion or activity that repeats itself

• A variable is any changed or changing factor used to test a hypothesis or prediction in an investigation that could affect the results.(WA State Standard)

What change in your pendulum might change the number of swings in 15 seconds?

• List possible variables:–Mass of the bob (# of pennies)–Release Position (hold the mass higher

or lower)–Length (use different lengths of strings)

Next Step: Now it is time for your design team to gather data and information to help solve our problem

Now you and your design Team will test different variables to determine what could be affecting the Super Sunset Swing to malfunction!

We will test: • Release position• Mass• String Length

New Vocabulary (WA State Standards)

• Controlled Experiment: A laboratory investigation in which the values of all variables are kept the same except for one that is changed from trial to trial

• Manipulated (independent) variable: The factor of a system being investigated that is changed to determine that factor’s relationship to the dependent (responding) variable.

• Responding (dependent) variable: The factor of a system being investigated that changes in response to the manipulated (independent) variable and is measured.

• Relationship: Connections observed among systems or variables. (Example: Cause and Effect)

Analyzing and sharing your data

• Analyze your data tables and graphs from the 3 manipulated variable tests, identify the relationship between the length of string and number of pendulum swings in 15 seconds.

• Did changing the length (manipulated variable) affect the number of swings (responding variable)

• The longer the _____________ the _________swings• The shorter the ____________ the _________ swings• The greater the number of swings, the _______ the pendulum• The fewer the number of swings, the ________ the pendulum

Claim-Evidence-Reasoning (CER)

• Now it is time to communicate your findings to Suzy Swingsalot and explain why her swing is not functioning as advertised!

• First, You are going to need to provide an answer to the problem (claim)

• Next, You are going to need to provide evidence from your pendulum model test that supports your claim.

• Finally, you need to explain your reasoning that explains the relationship (connection) that shows how the evidence supports your claim.

Question/Problem: What factor is causing the swing to malfunction?

• After analyzing your data on testing swing length, mass, and release write a claim that answers the original question.

• (Claim) The reason the swing is not swinging evenly is because______________________________________

______________________________________________________________________________________________

Evidence: Using your graph and data table, provide scientific data that supports your claim. Be sure it is appropriate and sufficient to support the

claim! Be sure to include appropriate units of measurement

Sentence Starters:• The data shows…. • The data from the graph illustrates…• According to the data table…• The next piece of evidence…• After analyzing the data, it is obvious that…

• Reasoning: This is where you explain how & why the evidence supports the claim.

How to connect evidence & claim with reasoning:• In an experiment, reasoning explains how the manipulated variables

affects the responding variable (cause and effect relationships)

• Include scientific principles that explains how the evidence supports the claim

Engineering Challenge!

• From what you have learned from your investigations, it is time to write back and provide Suzy Swingsalot an answer to why her Sunset Surprise Swing is malfunctioning. In your letter include:

• Part 1: Claim-Evidence-Reasoning so she will have a scientific answer backed up with evidence

• Part 2: A labeled Model of how you could fix her problem with the tree set-up she has. (See Engineering Design)

Engineering Challenge!