Looking for fun ways to engage your students without having to purchase a whole pile of new supplies? Science World has a simple and cute "bullfrog caller" activity for you. In this craft, students use a plastic cup and string to make their own instrument inspired by the Brazilian Cuica. Then they can answer questions about sound such as "what is the role of the cup?" and "where does the initial vibration come from?"

See the full bullfrog caller craft instructions (including a video!) at Science World.

If you'd like to use this craft as a jumping off point for a lesson on frog calls before heading out to have a listen, there are a number of online sources you can use to practice identifying frogs by their sounds:

• Calls of Frogs and Toads of the Northeast from Lang Elliott's Music of Nature
• Florida Frog Calls from the Florida Museum
• Frog & Toad Calls from the Indiana Department of Natural Resources
• Frog and Toad Calls from the Upper Midwest Environmental Sciences Center
• California Frog and Toad Calls from CaliforniaHerps.com