Kids love slime. Make a batch before they arrive so it peaks their interest when they see it. Let them examine it and make their own. When they ask how, tell them they have to gently squeeze ten frogs and slowly drip it out. They just might believe you, the slime is that gooey.
The easiest way to make a slime is to slowly add and mix water to corn starch until it is the gooey consistency you want. Add a drop of green food coloring to make it look like it came from an amphibian. Let the kids play with the amphibian slime and discuss slimy amphibians versus scaly reptiles. Continue your comparisons using the Free Download of the LilyPad Venn Diagram lesson in Hop Into Action, The Amphibian Curriculum for Grades K-4.
David Alexander is author of the Buzz Into Action & Hop Into Action Science Curricula. He specializes in making nature accessible to people and wildlife. You can follow him at www.natureintoaction.com