Quick overview: Desmos is a powerful graphing calculator that works in a web browser or on Apple iOS devices. Desmos can graph color coded functions, plot tables of data, transformations, and more. Free!
What does the tool do? To start, here’s a simple example of an intercept slope from the Desmos website. For other possible uses, I’ll provide you with a description from the Desmos website, “The calculator can instantly plot any equation, from lines and parabolas up through derivatives and Fourier series. Data tables open up a world of curve-fitting and modeling. Sliders make it a breeze to demonstrate function transformations. As browser-based HTML5 technology, the graphing calculator works on any computer or tablet without requiring any downloads. It’s intuitive, beautiful math. And best of all: it’s completely free!”
How can I use it in the classroom? Use the tool as another way to explain trickier concepts to students. For a more student centered approach, you could allow your students to experiment with the tool on your Interactive White Board (SMARTBoard) during the hands-on portion of class. Students can also use the Demos app on an iPad/iPhone to pick apart and play with equations at their own desk. (Source: Adam Bellow’s “Make Your Classroom Rock” ISTE 2013, San Antonio)