Growing Gators

Introduction:

Students learn concepts through concrete experiences with real things. In this long-term exploration,  students practice estimating, observing, measuring, and analyzing as they grow (and then shrink) an amazing water-loving gator. We recommend you name your gator as students will quickly adopt it as a class pet/mascot. The gator is made from super-absorbing polymer substance that is simply outstanding at absorbing water.  Over the course of a week or so, the tiny gator grows to over three times it's original length and over 20 times it's original mass. Then, the massive beast can be pulled from his pond and measurements continued as the gator slowly shrinks (about 2 weeks) to its original size.  Depending on the age of your students you can calculate the length, mass, area and even the volume of the gator. The changing measurements over time also makes a great opportunity for students to graph and analyze their data. 

Georgia Performance Standard's 

Science: Students will compute, estimate and analyze data. (S(K-5)CS2) 

Students will use tools and instruments for observing, measuring, and manipulating. (S(K-5)CS4)   

Mathematics:   A variety of measurement related standards can be applied depending on the age of the class.  For example, 

1st Grade: Students will compare and order the length and weight of objects using nonstandard units (M1M1).

2nd Grade: Students will understand the standard units of inch, foot, yard, meter etc (M2M1). 

5th Grade: Students will determine the area of geometric figures(M5M1).    

Materials:

Gro-Beast Alligator                          Plastic Container (pond)                Water            

Ruler                                                   Scale/Balance                                 Paper Towels 

Exploration:  

Procedure: 

1. Using the attached Gator Growth Chart as a guide, construct your own gator growth chart depending on the age of your students. Make sure to name your gator as kids will quickly become attached. 

2. Show students the gator and let each of them touch and feel it quickly. 

3. Have each student estimate the length and the mass (weight) of the gator. Then, as a class, agree on an  estimate of the length and mass of the gator. Record the estimates on your Gator Growth Chart.  Briefly discuss how scientists use estimates to help them solve problems in science. 

3. Have one group (3-4 students) measure and record the actual length and mass of the gator on the  Gator Growth Chart.  Place the gator in his pond of water and allow students to observe the growth of the gator during the day.

4. For each additional day, have another group of students measure and record the length and mass of the gator as she continues to grow.  Carefully remove the gator from the water and use a paper towel to pat her dry before you make the measurements. Record results daily on your Gator Growth Chart. 

5.  Continue these measurements until the gator becomes full grown (two or more days of no growth).

6.  Use line graphs or bar charts to graph the growth of the gator over time.

7. If time permits, remove the gator from the water and repeat the above process as the gator shrinks over time. She will eventually reach her original size.  The shrinking  process takes longer because we all know that it is easier to gain weight than to lose weight.     

Essential Questions:

1. Describe how you think the gator is able to grow so big?

    3.   How does the growth of the gator over time compare to the way kids grow? 

Explanation:

This is a great activity because it is fun engaging for students and it provides an extended chance for them to practice estimating, observing, measuring, and graphing.  Your students will literally run to the pond each morning to check on the growth of the gator.

Concept Discussion:

The gator is made from a polymer (repeating unit) molecule that has an outstanding ability to absorb water.  These kind of molecules are called super-absorbers and similar ones are used in diapers to absorb urine (which is mostly water). Substances, including water,  usually move from where is more crowded to where it is less crowded (from higher to lower concentrations). The water molecules move into the "gator" molecules because there is less water on the inside of the gator then there this on the outside.  This causes the gator to grow.

But the main purpose of this activity is the opportunity for students to observe, measure, and graph. Depending on the age of your students, you should consider whether it is best to use non-standard units like a paper clip or standard units like an inch.  You can also have kids graph the data in a variety of ways.  As an alternative to a whole class activity, this also makes a great small group or take-home project if you can purchase enough gators (about $2).  

Teacher’s Guide: Growing (Gro-Beast) gators can be purchased inexpensively from Educational Innovations at www.teachersource.com. They can also often be found at local toy stores and our often available in a wide variety of animal shapes.   The gators can also be used over and over for years.  Please try to keep the gator out of direct sunlight as it tends to breakdown the polymer from which the gator is made. 

Evaluation and Closure:

      Student activity sheets should be evaluated to check for student understanding. A rubric for this activity can be found at the following link:   Activity Rubric

Gator Growth Chart                       

This is our class alligator.  Her name is ______________________.  We are going to make a pond for our gator and then put her in and watch her grow.  We love ___________ because she is ___________   and    _____________.  We are going to practice making estimates and measurements using our pet gator.  

After carefully observing our gator, we estimate that it is _________    ________   long.

After carefully observing our gator, we estimate that it weighs  _________  _________.   

After discussing our ideas, we estimate that when the gator is fully grown it will be _______   _________ long and weigh about ______    _________.   

We think it will take about ______ days before she becomes full grown.   

Each day, we will have one group of students, record the length and mass of the gator. The group will record the data on a chart like the one below for everyone else to see.