Introducing the Process of Investigative Science Using Crayfish

Author(s): Linda Akiyama

Lesson Overview

Grade level(s):

Grade 3

Subjects(s):

Biology/Life Science

Big ideas(s):

A living thing can sense and respond to changes in its environment.

Science progresses by asking meaningful questions and conducting careful investigations.

Scientists share their findings with other scientists to create a shared body of knowledge.

Vocabulary words:

Before lesson: shelter, basin, investigation, second hand on a clock
During lesson: testable question, prediction, procedure, data, conclusion,  environment, sense, respond

What you need:

An overhead of "Investigation Plan"(attachment), overhead projector

Eight basins filled with 3-4 cm of water that has had the chloromine removed, eight crayfish, eight shelters from the FOSS Structures of Life Kit.

Science journals to record data.

sentence strips with definitions of sense, respond and environment.

Grouping:

Part 1 - Whole class when planning investigation.

Part 2 - Pairs or trios when carrying out investigation, collecting data,  drawing conclusions, and improving the design of the investigation.

Setting:

classroom

Time needed:

Part 1: 30 minutes

Part 2: 60- 90 minutes, depending on the design of the investigation and length of Wrap Up discussion.

Author Name(s): 
Linda Akiyama
Summary: 

Students will be introduced to the process of doing investigative science and will become familiar with vocabulary used in the process of doing science.  Given a testable question and a set of materials, students will make predictions, and then design procedures to create a "fair test "with teacher guidance. The class will investigate where a crayfish will go when put in a basin of water with a small shelter inside the basin.

Prerequisites for students: 

A prerequisite to teaching this lesson is to teach the previous lessons in the unit,  "What is Life and How Does a Living Thing Respond to Its Environment?"

 Previous Lessons:

1) What Do Living Things Have in Common?

2) Living or Non-living?

3) Introducing Cells

Learning goals/objectives for students: 

Investigation and experimentation
Students will be able to collect and use numerical data to describe and compare how crayfish respond when given a choice between being inside a shelter or outside a shelter when other crayfish are not present. Students will be able to predict the outcome of a simple investigation and compare the result with a prediction.

Life Sciences

Students know that one characteristic of all living things is their ability to sense and respond to their environment.

Getting ready: 

Make an overhead of "Investigation Plan"(attachment), fill eight basins from FOSS Structures of Life kit with 3-4 cm of water that has had the chloromine removed.

After part 1, make a photocopy of the filled out overhead for each student

Lesson Implementation / Outline

Introduction: 

  

Remind students that as a community of young scientists, they have been thinking and discussing what living things have in common. Tell the class that today they are going to look at something that most scientists agree is done by all living things. Write on the board: Most scientists agree that all living things sense and respond to their environments.

Introduce the word, "sense" - to recognize or detect something through using one's sense of sight, smell, taste, hearing, or feel. Next introduce the word, "environment" - anything outside of a living thing.

Have different students give an example of how he or she senses one thing in the environment. Ask students what parts of the body did they use to sense it. Ask what he or she did when the object was sensed. Introduce the term "respond"- how a living thing reacts after it senses something in it's environment.

Tell students that today they are going to work together to investigate how  one living thing, a crayfish, responds when it senses shelter in its environment.

Activity: 

Part 1 - Planning the investigation
1. Show experimental plan sheet on overhead.
2.  Introduce testable question: Scientists often start with a question that they want to answer by doing an experiment. Here is the question that I want to test.

    How will a crayfish respond when put in a basin with 3-4 cm of water that contains a shelter?

3. Ask students what they predict is the answer to the question.
4. Ask for their ideas on how we could do an experiment to find out the answer to the question. Discuss and come to consensus on the procedure and materials used and write this down in the appropriate place on the overhead.I would suggest that each group of students repeat the experiment at least 3 times. The investigation can be done in one session with short increments of recording. An example might be, "Check where the crayfish is at the end of 5 minutes, repeating 4 times." Or, it could be "Check every morning for four days." Students will fill out the rest of the plan on their own photocopied copy of the class experimental plan during Part 2 of the lesson.

5. Before the next science session, make a photocopy of the filled out overhead for each student

BREAK

Part 2 - Doing the investigation

6.Hand out photocopies of filled out "Investigation Plan" overhead, or display filled out "Investigation Plan"overhead.

7. Have groups pick up materials.

8. Have all groups follow the whole group investigation plan for the given number of trials. Have students create a data sheet to record their results. Depending on the investigation, this may contain a title, column listing each trial and time each piece of data is collected (examples: every 5 minutes for 20 minutes, once a day)

9. Convene as a group to share out results and create a chart of all the gathered data.

10. See Wrap Up and Closure

Checking for student understanding: 

Use data sheets and last sections of experimental plan to assess student understanding.

Wrap-up / Closure: 

Sharing Data and Drawing Conclusions- Have student pairs share their conclusions (answer to the testable question) and give evidence that supports their conclusions.

Tell students that scientists are always looking for ways to refine investigations so that they  are confident that their data is reliable. Lead a discussion on ways that the class investigation can be improved so that we could be more confident that the way the crayfish behaved in our investigation is closer to the way it would behave in the natural world when given a choice of shelter or no shelter.

Some discussion points:
     Do you think the crayfish had enough time to adjust to being in the new environment of the basin before we started recording where it was? Do you think it matters?
     What did you think about the amount of time we waited before we checked its location? Was it enough?Too much? Why do you think that?
     Did we do the investigation with enough different crayfish? Do you think all or most crayfish would behave like the crayfish that we used did?
     Do you think we would get more reliable data, data that we could count on showing where crayfish prefer to be, shelter or no shelter, if we did the investigation more or less times?
     Do you think the crayfish would react the same way when its dark at night? How could we test that at school?
     We didn't say where the observer should stand when observing the crayfish.Do you think that's important?
     Do you think crayfish would behave the same way if there were more crayfish in the basin? What observations or evidence do you have that makes you think that?

After the discussion students then fill out the last sections of the investigation sheet (summary of data, conclusions, what would you do to improve the experiment?) with their partner. This can also be done as a whole class.

Extensions and Reflections

Reflections: 

I  have students graph the data from the group data chart during math time. They will be asked later in the unit to show the data of their own investigations in graph or chart form for their science poster presentation.

Before moving on to Student Designed Investigations, I recommend teaching the lesson, Conducting Controlled Investigations: Example Using Sound, or a modified version appropriate for this unit

AttachmentSize
Investigation Plan.doc28 KB

California Standards - Grade 3

Life Sciences: 
3. Adaptations in physical structure or behavior may improve an organism's chance for survival. As a basis for understanding this concept:
c. Students know living things cause changes in the environment in which they live: some of these changes are detrimental to the organism or other organisms, and some are beneficial.
d. Students know when the environment changes, some plants and animals survive and reproduce; others die or move to new locations.
Investigation and Experimentation: 
5. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:
b. Differentiate evidence from opinion and know that scientists do not rely on claims or conclusions unless they are backed by observations that can be confirmed.
c. Use numerical data in describing and comparing objects, events, and measurements.
d. Predict the outcome of a simple investigation and compare the result with the prediction.
e. Collect data in an investigation and analyze those data to develop a logical conclusion.