Ewww . . . Worms - The Scientific Method In Action (Part 1 of 6)

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SWBAT follow the steps of the scientific method, assess the influence of the variable, and construct a data-based conclusion.

Big Idea

The students will complete the laboratory activity to determine the effect of the independent variable, temperature, on the dependent variable, the worm's heartbeat. This lab activity will reinforce the students' understanding of the scientific method.

Hook - Ewww . . . Worms!

5 minutes

This lesson grabs students' attention very quickly once they notice the worms that are crawling around my front demonstration counter!

We will waste no time and get right to work learning about our classroom visitors - WORMS!  When the students arrive to the classroom they will pick up three worksheets.  The first worksheet will be the opening activity which is an article providing Background Research Information about worms.  I ask that the students place the background research paper in a plastic sheet protector in an effort to keep it "clean" throughout the day.   The second and third worksheets the students will pick up will be used later in the lesson - Wormbeat- Student Record Worksheet and Wormbeat- Lab Procedure Worksheet.

The students will read the background information and record their answers on their lab worksheet.  Since today's opening activity is part of our lab, I will deviate from our classroom routine and not have the students record their responses on their bell question sheet. On lab days, I try to keep all of our lab activities and supplemental resources together to assist the students in their organization.

We will review the answers to this warm-up activity as a whole group before we progress to the lab portion of today's lesson.

Direct Instruction - Introducing Worm Beat

15 minutes

Since this is our first "real" lab activity of the school year, I wanted to front load the direct instruction portion of the lesson with a reminder of the lab safety features in the classroom.  I require students to wear safety goggles for this lab activity as a precaution and set the precedence that lab safety is a priority in the classroom.

I then physically demonstrate each step of the lab as it is described in the Wormbeat Procedure Worksheet to provide a visual example for my students.  This extra demonstration step takes a little longer but it assists in student learning and helps to meet the diverse learning needs of the students in the classroom. I also show the students where to obtain each of the necessary lab supplies for this activity so they are self-sufficient throughout the laboratory investigation.  When I set up the lab materials, I always place the supplies in the order that they will need them to complete the lab in order to create a flow so students can transition from one step in the lab to the next seamlessly. If possible, I also provide each set of lab partners with a supply tray to keep at their desk/table to help them stay organized and keep their lab station at their table tops neat.  

Once I have given the visual demonstration and verbally reviewed each step of the lab, I allow the lab partners to work through the required steps of the procedure at their own pace as they progress through the next portion of the lesson - Guided Practice.

My last words of advice to the students is to keep in mind the steps of the scientific method and how scientists test and manipulate variables in their laboratory experiments.  This lab was created to demonstrate each of the specific steps that was reviewed in the prior lesson - First Steps of the Scientific Method and specifically the Scientific Method Power PointPresentation.

Guided Practice - Discovering Worm Beat

30 minutes

The student lab partners will work independently during this portion of the lesson to follow the provided experimental procedure.  Students will record each of their observations and data on their Wormbeat Student Record Worksheet.  

I will circulate around the room and check in with each lab group to gauge progress and assist students in troubleshooting any trouble they might be experiencing.  I will also provide verbal announcements every 5 minutes as to the amount of time remaining so students can pace themselves to complete the lab by the end of the class period.  

Once the students have completed the lab's procedure, they will return their worm back to the supply container in the front of the room, dump out the water in the classroom sinks or outside planters, and clean up their lab stations.  Clean up in our classroom is a team effort and no one can leave until we have all cleared our lab stations.  This helps to build capacity among the students and foster the collaborative environment in the classroom.

 Since this is the first lab I had the group members pick a number 1-4 then I told them what each role was in their lab group.

Partner #1 - time keeper - measures 30 second intervals

Partner #2 - recorder - keeps track of data for the group

Partner #3 - worm wrangler - makes sure the worm does not get away

Partner #4 - pulse counter - measure the pulse by observing the dorsal artery

Students At Work

1 minutes

Here is a sample of my students working during the Worm Beat Lab.

Video Clip of students working in their lab groups attempting to count the pulse rate of their worm using the dorsal artery contractions.


Close - Sharing Data and Concluding Worm Beat

5 minutes

The final portion of this lesson is for the students to come to the front of the board and record the average data (the worm's heartbeat) from the three trials for both the control group (room temperature) and the variable group (cold water).  I ask all students to copy down the data on to their Student Record WS.  If we are short on time, I will take a picture of it and post it to our class website.  Here is a Sample Data for the Worm Beat Lab.

The students will complete the Conclusion Questions from the Student Record WS and graph the class average data.  Since we have not reviewed how to properly graph data yet this school year, I will guide the students in the creation of their lab graph.  As a class, we discuss how many sets of data we collected and have determined their that two sets of data - one for the control group (room temperature heart beat) and one for the variable group (cold water heart beat).  Then I will review independent and dependent variables and where they should be placed on the graph.  In the Worm Beat Lab,  the number of heart beats per minute is the dependent variable so it will go on the Y axis and the Group Number for each student lab group will go on the X axis.  

I advise the students to plot all of the data points for the control group first in one color and then connect the data points.  Then I encourage the students to plot the data points for the variable group in a different color and then have them connect the dots.  Since there are two sets of data on the same graph the students will need to create a legend to define which color represents which set of data.  We also quickly discuss the need for a title of the graph and the importance of scaling the graph so that it clearly represents the data.  Yes, there is a lot to review about graphing but I will rely on the students' prior knowledge to prevail and help them properly represent their lab data from today's investigation.  Here is a Sample Student Graph for the Worm Beat Lab.

As a final note, I will also remind the students of the homework assignment which is to complete the conclusion questions and construct the graph that we just discussed.

I have created a Grading Rubric to assist you in assessing student learning for this lab activity. I have also created an Answer Key to the Student Record Worksheet for you to use when reviewing the activity with your students.

In the next lesson students will take inspiration from today's experiment and design their own inquiry lab using our class set of worms . . . the fun continues in Biology!!!