Masher is a great, free, tool for creating video mash-ups. Masher offers a large collection of video clips from the BBC's Motion Gallery and Rip Curl video. There is a large music library, an effects library, and a good selection of video player skins. If you don't find content that you like in Masher's library, you can add your own images, video clips, and music clips through the Masher uploader. Masher also gives you the option to insert text throughout your videos.
Creating with Masher is a simple matter of dragging elements from the media gallery into the timeline editor. From there you can arrange the sequence of elements using the drag and drop interface.
Here is a sample Masher video from the Masher public library.
Here is a sample Masher video that I made.
Applications for Education
Video mash-up tools like Masher are great tools for students to use to showcase knowledge they've gained and information they've found. Masher allows students to create work they can be proud of. The work they create can be showcased in a blog, wiki, or website.
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