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Croc or Gator?



  • Science
    --Life Sciences


  • K-2
  • 3-5

Brief Description

Students in grades 2-4 read online information about crocodiles and alligators, write down the similarities and differences, and then create a Venn Diagram.


Students will:
  • read information online.
  • identify key differences and similarities between crocodiles and alligators.
  • write down the key similarities and differences.
  • draw a Venn Diagram showing those similarities and differences.


Venn Diagram, comparison contrast, alligators, crocodiles

Materials Needed

  • Pen and paper (a writing journal works well).
  • Student access to Microsoft Word
  • Student access to the Internet.

Lesson Plan

This lesson can be used either to introduce or reinforce Venn Diagrams and the concept of compare/contrast.

Begin by asking two students to stand up. Ask the class to name three things about their appearances that both students have in common. Examples might include, "Both have on socks" or "Both have on white sneakers." Write those ideas on the chalkboard. Then ask the class to identify three differences in their appearances, such as "Marta has blue hair bands, but Jessica has a red headband." Write those down as well. You then either can draw a Venn Diagram yourself and show students where each concept fits in the diagram, or -- if this is a review -- you can ask students to draw the diagram or walk you through a drawing.

Next, tell students they are going to practice finding differences and similarities with a subject they can "sink their teeth into" -- crocodiles and alligators.

Provide students with the directions below: (Instructions either can be demonstrated aloud for the entire class or typed out and put beside classroom computers.

  • On the Internet, go to Animal Bytes: Alligator & Crocodile, a site maintained by the San Diego Zoo.
    To make this activity easier for younger students, go to the site on each computer before class, and then drag the panda icon (next to the URL in the Address blank) to the computer's Desktop. That puts a shortcut on the Desktop, so students only need to double-click that icon to go to the Web site. Note that you can even click once on the shortcut and rename it Crocodile or Alligator to make it easier for students to read.
  • Read the main text in the white rectangle. (Note: Younger students (in 2nd - 3rd grade) might need to read only down to "Coming to Their Senses," while those in upper elementary grades can read the entire page.)
  • As you read the text, write down 3-5 things alligators and crocodiles have in common and 3-5 differences between them.
  • Open Microsoft Word (or another word processing program). Write your name and the date, at the top of the page, and then type at least six sentences about alligators and crocodiles. Each sentence should either tell one way in which alligators and crocodiles are the same or one way in which they're different.
  • Hit RETURN twice.
  • Check to see if the Drawing Toolbar is open. If it's not, click View>Toolbars>Drawing.
  • On the Drawing toolbar, click the icon (picture) that looks like a circle, square, and triangle, click "Basic Shapes," and then click the circle icon.
  • Hold down the mouse and draw two connected circles to create a Venn Diagram. Be sure to click the paint can icon and select No Fill so you can see all the lines of both circles.
  • Click the Text Box icon, click above one circle and type "Crocodiles." Click the Text Box icon again, click above the other circle and type "Alligators."
  • Click in the circle under Alligators and type the characteristics you've learned that alligators have, but crocodiles don't. Click in the circle under Crocodiles and type the characteristics you've learned that crocodiles have, but alligators don't. Click in the overlapping section of the circle and type the characteristics that alligators and crocodiles share.
    Alternatively, have students go to
    tools_templates/index.shtml#graphicOrganizers Graphic Organizers, click 2-Circle Venn Diagram, click File > Save As, and save the document to their Desktops. Students now can type in that Venn Diagram and save it to their computers.
  • Get your work approved, and then print or save it as directed.


Students are assessed on their
  • ability to identify differences and similarities.
  • ability to create a Venn Diagram with correct labels.

Lesson Plan Source

Education World

Submitted By

Lorrie Jackson

National Standards

NS.K-4.1 Science as Inquiry
NS.K-4.3 Life Science