Lesson 8

Introduction to Controlled Experiments: Plaid Pete Guides the Way!

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SWBAT identify the parts of a controlled experiment.

Big Idea

What are the parts of a controlled experiment? A funny book of failed experiments, a monster in charge of the laboratory over spring break, and a guidebook from Plaid Pete, help students to figure out the parts and have some fun along the way.

Setting Up the Investigation

Connection to The Next Generation Science Standards

In this investigation, students begin the work that will lead to their ability to demonstrate the following Science Practices; conduct an investigation collaboratively to produce data to serve as the basis for evidence, using fair tests in which variables are controlled and the number of trials considered (5-PS1-4); measure quantities such as weight to address scientific problems (5-PS1-3); and demonstrate the Crosscutting Concept of using a cause and effect relationship to explain change (5-PS1-4).

Although the Next Generation Science Standards do not require that 5th Grade students be able to identify the independent and dependent variables in a controlled experiment, they will have to do so in 6th Grade.  In addition, some states, such as Washington (where I teach) do require students to identify these variables on their state assessments.  Further, they are not named as independent and dependent variables, but as the manipulated/changed and responding/measured variables.  In order to assist students and teachers during this transition, I have included those names as well.

The Preparation Time for This Investigation is approximately  10 minutes. (The first time you construct Plaid Pete's Planning Guides, allow an additional 45 minutes).

Materials Needed:

  • One copy of the book, 11 Experiments That Failed by Jenny Offill

Focus & Motivation

15 minutes

Read Aloud

I gather my students in our meeting area.  I remind them that yesterday we ended the lesson with a discussion about controlled experiments, and that I shared with them that before we could help Plaid Pete design his experiment, we had to know the parts of a controlled experiment.  

I tell them that I am starting today's Science lesson with a story of failure, in fact - I have 11 of them.  I let that quietly sink in for a moment.  I bring out the book, 11 Experiments That Failed by Jenny Offill.  And although it is a picture book written for younger students, my 5th Graders love it.  It has just enough humor, and the kinds of questions that resonate with every kid to keep them interested.  It is also a great book for introducing the parts of controlled experiments.  

I read the book aloud, and after we are finished laughing I tell my students, "See how clever this girl was!  She may not have had a record of success, but she did have the right idea.  I think there were some parts missing though.  Let's see if we can figure out all of the parts to a controlled experiment so we don't have failed experiments."

"Oh and by the way, students, please don't try these experiments at home - especially the one where she tries to grow fungus in her brother's shoes!  I like happy parent phone calls.  And while we are at it, NO!  Your teacher does not like bologna on her face - even if it is a Science experiment!"

Share Lesson 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 lesson objectives and success criteria:

Learning Objective:  I can identify and name the parts of a controlled experiment.

Language Objective:  I can recount a short sequence of events in order.  [ELP.4-5.9]

Success Criteria:  I can name the parts of a controlled experiment when my teacher randomly calls on me. 

Guided Instruction

30 minutes

Analyzing the Video

Note:  I have explained to my students that we have this strange situation on our state assessment at 5th Grade that the independent variable is called the manipulated/changed variable, and the dependent variable is called the responding/measured variable.  Then it changes back to the independent and dependent variable in middle school.  

I want them to be familiar with the terms independent and dependent variable, because they will need to know them next year.  Because I am sharing materials with others, I am including both.  My students think that is a good idea.

I have my easel with a piece of chart paper that is headed at the top with the words:  How to Plan a Controlled Experiment.

I tell my students, "A controlled experiment has identifiable parts.  It doesn't matter what phenomena are being investigated, these parts are always present.  To help us begin to understand the parts and get a sense of why they are there, I am going to show you a video of a controlled experiment."

I tell them, "As you watch the video, I am going to be stopping it at specific places, and asking some questions that will help us figure out how this experiment was planned- so listen carefully!

(Note:  The creator of the video has unfortunately misspelled the word independent.  However, the video does such a good job explaining the variables in a controlled experiment, that I use it anyway.)

I play the video until it reaches .50, and then stop it.  This is the point where Jacob identifies the question.  

I ask my students, "What is Mr. Koning testing?"   I have them turn and talk to the person sitting next to them, and then call on students to respond.  When a student has responded correctly (He's testing how much the plant grows based on how much water it gets), I say, "Yes - and this "test" in a Controlled Experiment is written as a question.  So, the first part of a controlled experiment is Asking A Testable Question - a question that can be tested.  

Underneath my heading I write:  

1.  Ask a Testable Question 

(I leave a space in between each of the numbered items, as I will be coming back to add information in later lessons.  When I have finished I will have 6 numbered items fairly evenly distributed throughout the page).

I tell students, "The next 2 parts of a Controlled Experiment aren't shown in this video, so I am going to write them here.  The second step is where the scientists makes a type of prediction called a hypothesis - a cause and effect statement based on observation and previous knowkedge about what he thinks might be the results of his experiment."

 Underneath 1., I write:  

2.  Construct a Hypothesis

I tell students, "It also doesn't show this part in the video, but I bet when Mr. Koning was planning his experiment, he did what all good scientists do at the beginning of their plan.  He more than likely drew a picture of what his experiment would look like.  We call that an investigation set-up diagram.  And I am certain he made a materials list, so he would have everything ready before he began his experiment.  (Again - leave some room to add items to the bulleted list)

Underneath 2., I write:  

3.  Plan a Procedure & Investigate

  • Include a Materials List (Leave space because you will come back and add to this bullet)
  • Include an Investigation Set-Up Diagram

I play the video until it reaches 1.57, and then stop it.  This is the point where Mr. Koning states that you can only change one thing at a time and that everything else must stay the same.  

I ask students to turn and talk to the person sitting next to them and answer the question, "What was an important piece of information you heard about Controlled Experiments that we need to consider when planning ours?"  I know that it is critical that I give a few moments for students to talk.  I move between the pairs, listening in to their conversation.  

After I have heard a few pairs comment about keeping everything the same except for the one thing being tested - I make a big deal out of it - loudly saying, "Oh wow did you hear that?  You guys are so smart.  I heard over and over again - partners telling each other that all the variables had to be kept the same except for the one thing being tested.  Let's listen and see if there is anything else we need to know here."

I play the video until it reaches 3.50, and then stop it.  This is the point where Mr. Koning goes on Spring Break.

I tell students to turn and tell their partner what new information they learned about Controlled Experiments in this section that we need to include on our list.  I again am moving between partners, prompting and listening in.  In this section, students are going to be naming vocabulary.  I am listening for the following information that I will elicit from students after they have had an opportunity to talk to their partner, and then

I add the following bullets under item #3 (above) on the chart.

  • Include only one independent variable in each experiment (also known as the manipulated/changed variable)
  • Control all of the other variables (keep them the same) so that you will have a "fair experiment."

I play the remainder of the video.  

I tell students, there is one more piece of information we can add to our chart today.  Turn and tell your partner what it is.  I give them a minute or two, and then call on a student.  The student correctly responds with the term, "dependent variable."  I make certain that I get the complete answer and that it is the variable in the experiment that is measured.  I then tell students that it is also called the "responding/measured variable."  

Determining the Need for a Measurement Tool 

I then ask students, "How would we measure the dependent variable in an experiment?  Students respond with the specific tool in this circumstance, a ruler or meter stick.  I ask, "Is there any other way we might measure a dependent variable in a different experiment?"  It is important that they understand there are various ways that measurement is used in an experiment.  I finally elicit that some type of measurement tool is always needed.  

I add to the Materials List bullet under #3, so that it now looks like this:

  • Include a Materials List - must include some type of measurement tool to record the dependent variable (also known as the responding/measured variable).

I tell students that the last three items on our list are also not pictured in the video, but that we can infer step 4.  I ask them, "What do we get when we collect measurements and observations?"  I am looking for the answer, data.  I write:

4.  Collect Data

I then add the final two steps, again leaving space on the chart to add bulleted items in later.

5.  Analyze Data & Make A Claim

6.  Conclude/Communicate Findings

When I am done, this is the chart for How To Plan A Controlled Experiment

I tell students, "We will be adding to this list as we go, but we are now building a basic framework for how to Plan and Conduct a Controlled Experiment.  You have heard during this video that a controlled experiment has some very specific Science Vocabulary.  Let's return to our desks so we can add these to our Science Notebooks."

We almost don't get to the vocabulary because they beg me to play the video again.  They really like the part where Mr. Koning goes on Spring Break!  Just a warning . . . 


Vocabulary Instruction

10 minutes


Consistent with the 5E Model of Instruction - The majority of vocabulary instruction in my classroom occurs during the "Explain" or instructional stage.  This ensures that students have the experiential activities that will allow them to connect new vocabulary terms to conceptual understanding.

I present the four words from the What's The Matter Plaid Pete?- Word Wall Cards Lesson 8 using the same instructional routine outlined in a previous lesson.  In this particular case, I will give considerably more support, as students will not be as adept with these four words as they would with others.  They are new to both their listening and speaking vocabularies:

  1. Say the word to students.
  2. Ask students to repeat the word at least 5 times.  For example, I will say, "Say it to the window.  Say it to my hand.  Say it to the door.  Say it to the ceiling."
  3. I say the word in context.  For example, I will say, " The position the plants were placed in was one of the controlled variables in the video."  
  4. I will then randomly call on a student to use the word in a sentence, giving successive prompts to assist them, if needed.

Science Notebooks

I also use the same Science Notebook routine as was used in previous lessons:

After introducing the words, I again demonstrate for students how to make a three column table with rows for each of the eight vocabulary words.  I model for them in my own Science Notebook how to write the word in the first box, a non-linguistic (e.g. picture) representation of the word in the second box, and work with the class to generate an example sentence for the first word in the third box.  Students cut out their copies of the cards and place in the envelope, which they glue on the page behind their table.  They will finish sentences for the remaining seven words either for homework, or for seat-work later.  A completed notebook will look like Example 1

Examining student work can also reveal conceptual errors, as in Example 2.  This student doesn't really understand what a "measured/responding variable" is, and will require re-teaching.  It is important to catch these misconceptions early so that students don't continue to build on them.

Reflection & Closure

10 minutes

Plaid Pete's Guide to Controlled Experiments

I tell my students that we have learned the basic steps of a controlled experiment, but  I have something Plaid Pete has prepared that should help them out tomorrow when we need to be more specific.  I hand each student pair a copy of Plaid Pete's Guide to Planning A Controlled Experiment

I give students a few moments to look through the guides and ask them what they notice.  I have them turn and tell the partner next to them, and then randomly call on pairs to share out.  I hear, "Wow, I didn't know there were so many steps in experiments!" And, "I didn't know we did experiments like this in 5th Grade!"   

They want to talk about controlled experiments, and how they are different from the investigations we have previously done.  It is an excellent time for some paired academic discussion!  In Video Clip 1, this student is discussing the fact that controlled experiments can show a cause and effect relationship.  In Video Clip 2, this student is sharing with his partner some of the advantages of controlled experiments.  I want to assess the lesson objective, and randomly call on students to name the steps in a controlled experiment.  This is new language for my students, and many still need to rely on the chart for assistance.  I know that they will need multiple opportunities to engage in controlled experiments before this becomes a part of their spoken language. 

I wanted them to be a bit awed and excited about planning their very first experiment - and I think I succeeded!  I finish by telling them that tomorrow we will begin planning our controlled experiment, with Plaid Pete guiding the way.