Plaid Pete Puts the "Fair" in Test!

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SWBAT collaboratively plan and carry out fair tests in which variables are controlled and failure points are considered, to identify aspects of a model or prototype that can be improved.

Big Idea

How does a prototype design change through multiple trials? Students redesign their water filtration systems, and redesign again; coming to understand how the iterative process of engineering design improves an original prototype through trial and error.

Setting Up the Investigation

Connection to The Next Generation Science Standards

In this investigation, students finish the work that will lead them to explore the Disciplinary Core Idea of Earth and Human Activity -  that human activities in agriculture, industry, and everyday life have had major effects on the land, vegetation, streams, ocean, air, and even outer space.  But individuals and communities are doing things to protect Earth's resources and environments. (5-ESS3-1); the Disciplinary Core Idea of Engineering Design - that possible solutions to a problem are limited by available materials and resources (constraints).  The success of a designed solution is determined by considering the desired features of a solution (criteria). Different proposals for a solution can be compared on the basis of how each one meets the specified criteria for success or how well each takes the constraints into account.  (3-5 ETS1-1); Research on a problem should be carried out before beginning to design a solution.  Testing a solution involves investigating how well it performs under a range of likely conditions.  (3-5 ETS1-2).  At whatever stage, communicating with peers about proposed solutions is an important part of the design process, and shared ideas can lead to improved designs. (3-5 ETS1-2); Tests are often designed to identify failure points or difficulties, which suggest the elements of the design that need to be improved.  (3-5 ETS1-3); Different solutions need to be tested in order to determine which of them best solves the problem, given the criteria and constraints.  (3-5 ETS1-3); and the Crosscutting Concept of Influence of Engineering, Technology, and Science on Society and the Natural World  - People's needs and wants change over time, as do their demands for new and improved technologies (3-5-ETS1-1), and Engineers improve existing technologies or develop new ones to increase their benefits, decrease known risks, and meet societal demands (3-5-ETS1-2).

Please Note:  The Lexile Level for Plaid Pete Engineers A Solution - Lab Scenario Sheet Lesson 10 is 790 (5th Grade Range is 740 - 1010).

The Preparation Time for This Investigation is approximately 10 minutes.

Materials Needed:

One copy for each student of Plaid Pete Engineers A Solution - Lab Scenario Sheet - Lesson 10

One copy for each student of The Adapted Informed Design Rubric (This is a simplified version of the NSTA published version)

One copy for each student of Plaid Pete Engineers A Solution - Design Portfolio (handed out in a previous lesson)

Filter Materials From Yesterday's Lesson:  Team Plaid Pete Has the Blueprint for Success

One filter system for each team (2 liter pop bottle, cut in half with top inverted and bottom used as a stand) NOTE TO SELF - INSERT PIC HERE

Playground Sand

Aquarium Gravel

Screen Material - Cut into 4 inch squares

Cheesecloth - Cut into 4 inch Squares

Coffee Paper Filters

Cotton Balls

Graduated Cylinders - 1 per team

Timers - 1 per team

Vials - 1 per team and 5 additional for Water Clarity Samples

Small Tubs - 1 per team

Measuring Cups

Tape Measure - 1 per team

Ruler - 1 per team

"Contaminated Water" - 1 Liter of water to which dirt, mud, sand, and small rocks have been added.  

Focus & Motivation

15 minutes

Introduce the Scenario

I tell my students, "After looking over your Design Portfolio's yesterday, I am noticing that some of you had some difficulty with Trial 1.  In fact, it is the same difficulty that Plaid Pete's Team had.  I want you to read today's scenario carefully, because when everyone is finished, we are going to discuss it together!"

I pass out the Plaid Pete Engineers A Solution - Lab Scenario Sheet - Lesson 10 and my students get out their highlighters.  I tell them there are 3 reader's theater parts, Plaid Pete, Logan, and a narrator.  We determine who will read the parts and begin.

Class Discussion

After we have finished reading the scenario.  I ask my students to take a moment of quiet think time and answer this question that I have posted on the white board:  What problem did Plaid Pete's Team have?  Why was this a problem?  When my students have had a moment to think, I ask them to turn and talk in their teams and discuss their answers.

I call on a student who easily answers that Plaid Pete changed too many things at a time, and that it made it hard for him to know what worked and what didn't.  I know this discussion today is absolutely critical.  I have some students who still do not get the idea of a "fair test", either in a controlled experiment, or in an engineering design situation.  This is the perfect opportunity for them to experience it in a real world situation.  

I share today's learning objectives and success criteria. 

Learning Objective & Success Criteria

Note:  Consistent with the Sheltered Instruction Observation Protocol, I am now including a language objective with each lesson.  These objectives were derived from the Washington State ELP Standards Frameworks that are correlated with the CCSS and the NGSS.

I share the learning objective and success criteria.  I specifically remind my students about the components of the Science Team Evaluation Rubric.  This is the kind of activity that can breed problems - it's competitive, students can differing ideas about how to make things work; frustration can get in the way of success; and students can often have difficulty listening to each other in the heat of the moment.  These are real world situations that students need practice with.  The Science Team Evaluation Rubric will provide a scaffold so that they can do that practice - with support.  Putting the Science Team Evaluation in Place will provide support for those students who need that reminder:

Learning Objective:  I can collaboratively plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.

Language Objective:  I can engage effectively in collaborative discussions, building on other's ideas and expressing my own clearly.  [ELP.4-5.2]

Success Criteria:  I can achieve a "meets standard" score on the Science Team Evaluation Rubric, as measured by my peers.  

After I have shared the learning objectives and success criteria I tell my students, "Now that we are very clear about what a fair test is, I want to see all teams conducting fair tests for Trials 2 and 3.  Let's review the "signposts" that were posted yesterday to guide us through this process."  I direct my student's attention to the whiteboard.

Team Activity

45 minutes


I have a clipboard on which I have placed one copy of The Adapted Informed Design Rubric for each of my students.  I have placed them in groups by team, so that I can easily access them.  I tell my students, "As you are working today, I am going to be assessing each of you individually as you work in your teams.  I will use both the observations I am making today, as well as the evidence you leave me in your Design Portfolios to determine your score for this unit."  I direct their attention to the rubric on page 3 of the Design Portfolio and briefly review the items listed.  I then direct their attention to the scoring guide on page 2 of the portfolio.  I answer any student questions, and then tell students to get ready to listen for the directions for today.

Introduce the Signposts for Today

I have revised yesterday's Signposts to fit today's activities.  I go through these step by step with my students to ensure that they understand exactly what they are to do.  In the past, I have had to monitor each step.  However, my scientists are better learning how to manage themselves during investigations and it is important that I allow for gradual release of responsibility to them, while providing the supports necessary for them to be successful. These "signposts" are one such support.  I know that I will need to redirect a few of my scientists, pointing to the whiteboard and asking the question, "What is it that you are supposed to be doing now?"

Step 1:  Collaboratively revise your design idea, using the information from Trial 1.  You will create a new prototype design on Page 11 of your Design Portfolio.

Step 2:  Draw your blueprint - everyone must have a blueprint of the prototype with measurements and labels.

Step 3:  Construct your prototype according to the blueprint - ask yourself the  3 prompts at the top of Page 12 of your Design Portfolio (Because I will!).

Step 4:  Get my approval for your blueprint before you retrieve your materials.  Include a "job list" for your team.  Everyone must have a role!

Step 5:  Construct your prototype.

Step 6:  Run Trial 2, using 100mL of water and a timer.

Step 7:  Answer the Prompts on Page 11 of your Design Portfolio.

Step 8: Follow the same steps for Trial 3, drawing the blueprint of your prototype on page 13 of your Design Portfolio, and answering the questions on page 14.

WARNING!  Even though water may be filtered and look clean - it has not been disinfected and is not safe for drinking!

When I am certain that all students have attended to and understand the directions, I release my teams to begin.  I am carefully monitoring their efforts!

Attending to Failure Points

When I see that most teams have conducted Trial 2, I stop the activity for a moment and get their attention.  I ask the question, "Who remembers the information I gave about failure points during yesterday's investigation?"  I am not surprised to see very few hands raised.  I revise my question.  "What is a failure point?"  I call on a student who responds, "It is the point in the design where the system isn't working."

I ask, "When a design fails,  do you immediately just rush in and start changing things?"  I call on a student who answers, "No."  Then I ask, "Why not?"  Another student responds, "If you change more than one thing at the same time, you won't know exactly what caused the failure, or what fixed it."

I agree that this is correct, I also tell my students, "When you have a system, like the water filtration systems you are constructing, all of the pieces work together to make the system function.  When one part of the system is not working, it affects the ability of the entire system to function appropriately.  It's important if a system is not working properly to stop and look at each piece of the system to determine where the problem is.  For example, if water is not moving through your filter system, what are the parts of the system that you will need to look at?"  I call on a student who responds, "Well, you would need to look at each of the materials you are using.  And then there is the filter system itself.  You would probably need to look at that too."  I affirm this student's answer and caution my teams, "When you have a failure point in your system, don't rush in and start changing things. Stop and analyze your failure points carefully, list the failure points you have identified in your Design Portfolio.  Look at them as an opportunity to create a better design.  Then pick one thing at a time to change and test."

I think I worried too much that these kids wouldn't attend to their failure points.  I fort that this is a competition, and they are really paying attention.  In this Video Clip 1 of the second trial, this team experiences a failure point, but by Video Clip 2 - they have solved their problem, as well as engaging in a little market research to make their design more competitive.  

At the end of the 3rd Trial, teams submit their samples, along with the cost.  We have a clear winner!

I give the signal to clean up and get ready to begin their final evaluations.

Reflection & Closure

15 minutes

Teams Evaluate Final Prototype

After my teams have finished Trial 3, they get their Design Portfolios and turn to page 15. They begin drawing a diagram of their final design and answering the evaluation questions.

I have them work to complete this page, following the prompts to list how their prototype changed from the beginning to the end; good points of the final design; and possible improvements to the final design.


Notebook Revision

When students are finished with their evaluation, I tell them to return to the first page of this unit in their Science Notebooks, where they have written the first Big Idea for this unit on the bottom top half of the page:

 Big Idea #1:  Communities use science ideas to protect the Earth's resources and environment.

I read this Big Idea out loud.  I ask students to think about all they have learned in this unit, and to create a picture or series of pictures on this half of the page that best represents their new learning. I give students time to complete their rough draft, letting them know we will have time at the end to color in the pictures.  I then read the second Big Idea.

Big Idea #2:  Engineers use systematic practices of research and design to find solutions to human problems. 

I ask them to do the same thing - create a picture or series of pictures on the bottom half of the page where they have written this big idea that best represents their new learning.

This is another assessment piece that will give me a window into student understanding.  It is also a way I can compare my written assessment with the pictorial representations of my English Language Learners.  It gives me another way to determine their acquisition of concepts without the interference of language and vocabulary.  I allow students time to work and then collect their notebooks.  This is a student example of one revision.