Comparing Seedlings #2

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SWBAT use qualitative and quantitative data to describe and compare seedlings.

Big Idea

It's time to check in with the seedlings! Are there too many leaves to count yet?

Instructional Notes

Prior to this lesson, students planted various kinds of bean seeds (see the lesson here!).  Then, about a week prior to this lesson, students measured and compared the bean sprouts.   Note: This lesson should be separated a week from the previous comparison lesson.

Today, again we measure and graph our data in order to work towards answering the question of which bean grows the tallest the fastest.  

First, students will use qualitative data to describe and draw their seedling.  Then, students use quantitative data to measure their seedling.  In this lesson, we use mathematical data to measure and then compare the seedlings.  This aligns to NGSS Science & Engineering Practice #5 Using Mathematics and Computational Thinking, as well as #4 Analyzing and Interpreting Data.

Finally, we come together as a class and graph the growth of the different bean seedlings.  Once we graph our data, we can compare and analyze the data to make predictions about which type of bean Jack may have had.

This lesson works towards NGSS standard 1-LS1-1 as we are identifying and naming external parts. It also works towards 1-LS3-1 as students will be comparing the seedlings to the adult plants as they continue to grow.

Warm-up: Planting the Seeds

5 minutes

To begin, we meet at the rug.  I set the purpose for the lesson by sharing the objective.

Today we will be using mathematical data to describe our seedlings.  It's been so exciting coming in each morning and seeing if they've grown.  Today, we'll record our observations like scientists.

Before we observe them formally, I display the data from our previous measurements.  I ask questions to get them thinking like mathematicians:

  • Will the height be greater or less than a week ago?
  • What do you predict will happen to the graph?

Exploration: Tending the Garden

30 minutes

I tell students that first we will describe our seedlings with words and drawings.  My room is arranged with groups of 4-6 desks.  I pass all seedlings for a particular type of bean to the same table (for example, the first table gets all of the lima bean sprouts).  

Students glue in a blank plant journal and record what they observe using drawings, words, and accurate colors.  It is important to point out the seed leaves, or original two leaves.  These are normally different in shape and you should be able to pick them out right away.

Next, as I sense that most students are finished, I play a transition song and bring students back to the carpet.  Transition songs allow stragglers to finish and all students to stretch their legs a bit!

When students return to the rug, I tell them that there are two kinds of data: qualitative and quantitative.  

The word "quantitative" has the word "quantity" in it. The word quantity means number.  How can we use numbers to describe our seedling?

I expect students to say that we can measure how tall the plant is and maybe count the leaves.  At the earliest stages of the plant, it is possible to actually count the leaves!  I review the measurement techniques (place the ruler on the surface of the soil and measure to the top of the bean sprout).  It is essential that all groups measure the same way.

Students are released back to their seats to measure and record using quantitative details.

Next, we return to the perimeter of the rug.  We pick the bean that is the tallest for each type, and we graph only its data.  Students record in graphs glued into their Science Journals.  

Closing: Harvest

5 minutes

You may want to consider extending the time of the closing to allow time for analyzing data.  NGSS Science and Engineering Practice #7 is Engaging in argument from evidence, which includes constructing an argument with evidence to support a claim. 

I play a transition song, during which I put the seedlings back in our grow lab and students bring their measurements to the rug.  

First, I ask open-ended questions that get students to started thinking like mathematicians.  I have students turn-and-talk to share their ideas

How have our graphs changed?  What do you notice about the graphs?

Finally, I get more specific with questions like these:

Which seedling is the tallest?  Which seedling is the shortest?  Which seedling (the tallest) may have been Jack's (from Jack and the Beanstalk)?  

As students share their answer, I follow-up with the question, "How do you know?"  Students then have to use the data to support the answer verbally.

Note: Depending on how long you allot for this unit, you can continue teaching this lesson each week (for example, every Tuesday is measure and data day.)  Even if the unit ends, feel free to keep the measurements and data going as long as you can!