Identifying Structures and Investigating Purpose

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Students will be able to create questions, investigate, and gather data regarding crayfish body structures.

Big Idea

It is critical for students to "remember" that their observations serve them well and lead to questions and problems that can be investigated in a scientific way. This lesson provides the space and interest to explore and question.


5 minutes

The question to guide today's session is, "What body structures do crayfish have and how do they help them survive?"

Mini Lesson

15 minutes

To begin our lesson, I will return to our powerpoint from the previous day.  I prompt the students to "wonder" about the crayfish's body and how the structures may or may not help it survive.  

In these two videos, you will notice my students communicating questions about the structures, without knowing the correct terms.  I allow them to express their questions anyway, as work today will introduce the terms. 

This student wonders about the "heaviness" of the shell and how it might slow the crayfish down, which would not help it survive. 

In this video, I had a chance to link their learning of plant adaptations to animal adaptations. The student in this clip notice a structure she thinks may help the animal survive. 

Following the group discussions and wonderings, I will explain to the students that they will examine a table of information and diagrams in order to determine what structures the crayfish has in order to help it survive.  This is when I teach them that we will call "what the structure does" as a function

Active Engagement

30 minutes

I will supply my students with a graphic taken from the FOSS kit, that our district uses, of a crayfish and a table of structures their functions.  Their task will be to decide which structure on the graphic matches those on in the table.  They will need to use the function description to help them do this matching. 

As you can see in this clip, though the activity is pretty straightforward, the students must compare structures, determine its possible purposes, and make sense of the information given to them.  I was able to ask this student a deeper question about "why" a crayfish would need a certain function.  This will guide the student develop an investigation in a future lesson on crayfish behavior.

Sharing and Closing

10 minutes

In order to close, I will go through the labeling with the students to make sure they have the correct information.  I will then ask students to discuss with me the function of each structure and what is important about them.  

I will use a student's work to do this and ask the other students to disagree or agree, based on their work. This is a great way to build a science community and promote debate among third graders. (SP7)