YouTube itself does not provide users with a way to download and save videos. They would prefer you visit their ad-supported site each time you view a video. Furthermore, YouTube videos are in the Flash format. While there are Flash players you can download, software like QuickTime and Windows Media Player do not usually play Flash video. So, not only do you need extract the video from the YouTube site, it also needs to be converted into a more compatible format. Although YouTube doesn't provide a way to download and convert its content, there are sites that specialize in helping folks do just that. I'll go through the steps of using Zamzar. This service downloads, converts, and then emails you a link to download the newly converted file.

1. From your home (or other location that doesn't block YouTube) locate and copy the URL (a.k.a. web address) of the video you wish to download from YouTube. The URL can be found in your browser's address bar. Additionally, you can copy the URL by clicking more info to the right of the video on the YouTube video page. I found this video that features NASA astronaut Don Pettit and a weightless sphere of water. The URL is http://www.youtube.com/watch?v=qxk3VqZZBsw.
   
   


2. Go to www.zamzar.com/url. In the Step 1 box, paste the video's URL. You may have to remove an extra http://. Click the Add URL button.
   
   


3. Complete Step 2 on the Zamzar page by selecting the movie format to convert to. MP4 is my preferred choice. It plays in QuickTime, iTunes, iMovie, and on iPods. However, if you are planning play the clip in Windows Media Player or import it into Windows Movie Maker, choose AVI.
   
   


4. For Step 3 enter your email address.


5. Click the Convert button in Step 4 to begin the process. Zamzar will confirm your settings in a dialog box. Click OK.
   
   
   


6. It will take a few moments to upload the video. You may then close your browser window and go about your business. Within an hour, you'll receive an email from Zamzar that contains a link for you to download the converted video. After downloading from Zamzar's link, you will want to rename the downloaded file to something more descriptive.
   
   
   

So now what? There are several options for getting this video to school:

Open Your Email at School

That link Zamzar to your email is good for 24 hours. That means you can open your email at school and download it there, probably on the computer you'll use to show the video. Hopefully Zamzar is not  blocked at school.

Take Your Laptop to School

If you downloaded the video to a laptop, take the laptop to school. Then use it to show the video on a projector or to copy the video to another computer.

Copy To a Flash Drive

After downloading the file, copy it to a flash drive or an iPod's hard disk space. Once at school, plug in the drive or iPod and copy the file to the computer you'll use to show the video. Similarly, you could burn the video onto a data CD and then play the video from that CD at school.

Sync To an iPod

Drag and drop the video file into the Movies section of iTunes. Sync a video-capable iPod, making sure the movie is set to sync to the device. At school, connect the iPod to a television or projector using an AV cable to play the video directly from the iPod. (You'll need to go into iPod's setting and turn on TV Out.)

Edit with iMovie or Movie Maker

iMovie (Macintosh only) can import MP4 files. Just drag and drop the video file from your desktop into your project. Movie Maker (Windows only) can import AVI files. Just choose File > Import Media Items. Now in iMovie or Movie Maker the YouTube clip can be edited as if the clip came from your digital camcorder. This is useful for removing content, combining videos, and adding text. Similarly, Mac users can embed an MP4 video into a PowerPoint slide show and Windows users can embed AVI.

Burn to a Video DVD

Whether or not you edit with iMovie or Movie Maker, the downloaded video can be burned to a DVD that will play in computers and DVD players. Macintosh users can drag and drop the MP4 video right into iDVD. Windows users, you'll need video DVD creation software, like Roxio MyDVD. Of course, you'll also need a computer with a DVD burner.

Another great source for free online video is TeacherTube. You can user Zamzar to download videos from TeacherTube in the same way you download them from YouTube. Whether downloading from TeacherTube or YouTube, be sure to honor the creator's copyright and to follow the site's Terms of Service.