Screencasting is a great way for teachers to create a "how to" video, a flipped video for content acquisition, or personalized materials for their classes.  Students can also use screencasting for their own presentation needs.  Here are some suggestions:

Screencast-o-matic is a program that works best when downloaded and installed, although it can work inside your browser. 

Screencastify is another popular choice.  It is an extension in your Chrome browser, and videos are automatically saved to your Drive. (Note: the free version is limited to video lengths of five minutes.)

For more information and a comparison of the two tools, read this blog entry.

However, for students with Chromebooks, keep in mind that the device now has a built in Screen Capture tool that would even work when not connected to the Internet!  For more information, read this blog entry.

Last but not least, Macbooks have a built-in screencasting option.  Click here to view a how-to video.