Comparing Seedlings

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

Big Idea

Jack's magic beanstalk grew so quickly! Students can use data to figure out which beans Jack may have had.

Instructional Notes

About one to two weeks prior to this lesson, students planted various kinds of bean seeds (see the lesson here!).  In the previous lesson, students determined how they would plant, label, and compare the sprouts in order to determine what kind of bean seeds Jack (from Jack and the Beanstalk) may have had.  

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

First, students will use qualitative data to describe and draw their seedling.  Then, students use quantitative data to measure their seedling.  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

In a previous lesson, students planned an investigation of plants in order to figure out which bean seed might have been Jack's.  Here is the original Investigation Notes Chart, including students' ideas about how we should measure each plant in order to compare them.

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.  First, we'll record what we see with drawings and words.  This is called qualitative data.

I pass out plant observation journal pages for each student to glue into their Science Journals.  Student draw and write to share their observations.  

Here are some sample student journals #1#2#3.

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.

Closing: Harvest

15 minutes

You may want to consider extending the time of the closing to allow time for analyzing data.

I play a transition song, during which I put the seedlings back in our grow lab and students bring their measurements to the rug.  I create a bar graph of each plant and it's height based on student measurements.  Students work along with me, recording on their own bar graph.

Here is our initial Data, followed by averages.  Then, I  created this bar graph showing the relative heights.

My class can't help comparing as we go and calling out comments like, "Ours is the biggest!"  Once all of the data has been entered onto the graph, I have students turn-and-talk to compare the data.  Which seeding is the tallest?  Which seedling is the shortest?  Which seedling (the tallest) may have been Jack's?  Students use data to support their answer verbally.

As a morning journal question the following day, I then have students write to justify their conclusions with a sentence frame, "I think the _____ seeds may have been the same as Jack's because _____."  In this way, students return to the graph the following day and use it as a room reference.

Here are some sample journals: