Obtaining Digital Materials

Index

Overview

To create flexible lessons, teachers can find digital text, images, sounds, and movies on myriad subjects. In this section we provide some sources for these materials, with basic instructions on how to obtain and work with different kinds of media.

Back to index

Copyright Law and Fair Use

Works that are in the public domain, because their copyright has expired or because the author has relinquished copyright, are often available for free. These works may be easy to find and download, and may be in fairly universal formats. Works that are still under copyright often have rigid protections associated with them. They are available for purchase or subscription, downloadable or on CD-ROM. Many are in a format that can only be used by a proprietary viewer, limiting their usability in a universally designed curriculum.

The Copyright Law of 1976 allows copyrighted materials to be used royalty-free for certain nonprofit educational purposes. According to 17 U.S.C. 107 educators may make copies of copyrighted works for use in teaching if:

• it is used to illustrate the lesson;
• the use is sufficiently unpremeditated that permission could not have been reasonably obtained in advance;
• the use has not been ordered from the teacher's superior; and
• the use does not replace purchase of the material.

It is also permissible to convert materials into other formats (17 U.S.C. 121), including electronic, braille, or audio, for the use of people with disabilities. It is not permissible to further distribute the reformatted information, the original copyright information must be copied into the new format, and notice that the reformatted version is also protected by that copyright must also be included.

A group of educators, publishers, and copyright holders (The Creative Incentive Coalition) drafted a set of guidelines in how the concept of "fair use" applies to multimedia applications.

• U.S. Copyright Office General Information and Publications

Back to index

Obtaining Digital Text

Digital text exists in an astounding number of formats. The simplest form is called ASCII text (filenames ending with a *.txt extension). ASCII text is a standard useable by any personal computer but contains almost no formatting. HTML (*.htm or *.html), used on Web pages, contains moderate formatting but is still relatively universal. Rich Text Format (*.rtf) is a variant of the Microsoft Word text format that is widely used.

If text that you download is not already in one of these formats, you may have to convert it in order to use it in your classroom. Common formats include major word processor formats, such as Microsoft Word (*.doc or *.rtf) or WordPerfect (*.wp6), Adobe Acrobat (*.pdf), and occasionally, proprietary formats used by an e-text distributor to ensure security. To convert word processor documents to digital text, you must have a copy of that word processor or a conversion utility. Adobe provides a free access service to convert Acrobat documents to HTML or plain text. (For more information check http://access.adobe.com/.) If the text requires a proprietary viewer, it may be difficult or impossible to convert the file: the point of the viewer is to prevent you from doing so. Contact the e-text distributor for assistance.

Following are some sources of digital text (for information on converting downloaded e-text files to a usable format, see Converting Downloaded Text Files):

• Alex: A Catalog of Electronic Texts on the Internet
  http://www.infomotions.com/alex/
  Catalogue with roughly 2,000 entries of e-texts, mostly on gopher servers

• American Library Association Great Sites
  http://www.ala.org/parentspage/greatsites/litw.html (black & white version)
  http://www.ala.org/parentspage/greatsites/lit.html (color version)
  Comprehensive list of links to literature and language Web sites for children

• Children's Literature Web Guide (University of Calgary)
  http://www.acs.ucalgary.ca/~dkbrown/
  Internet resources related to books for children and young adults

• Electric Library
  http://www.elibrary.com
  On-line research database containing: newspaper and magazine articles; works of literature; television, radio, and government transcripts; and reference materials such as an encyclopedia, a dictionary, and a thesaurus

• The Electronic Text Center
  http://etext.lib.virginia.edu/english.html
  An extensive listing of prose and poetry e-text available for downloading

• Electronic Texts Journals Newsletters Magazines and Collections
  http://www.lib.ncsu.edu/eresources
  On-line listings of sources of e-text of collected works, magazines, newsletters, and scholarly journals

• Etext Archive
  http://www.etext.org/
  Eclectic subject matter availabe to download as e-text

• Internet Public Library
  http://www.ipl.org/
  Links to picture books, short stories, poetry, myths, fables, magazines, and information about authors

• KidPub WWW Publishing
  http://www.kidpub.org/kidpub/
  Thousands of stories written by children all around the world

• Literature Online from Chadwyck
  http://lion.chadwyck.com/
  A fully searchable library of over 250,000 works of English and American literature

• On-Line Books Page
  http://digital.library.upenn.edu/books/
  Directory of sources for over 6000 on-line books

• Project Gutenberg
  http://www.promo.net/pg/
  http://www.gutenberg.net/
  Light literature (such as Alice in Wonderland, Peter Pan, or Aesop's Fables), heavy literature (such as Moby Dick or Paradise Lost), and references (such as almanacs, encyclopedias, or dictionaries) in downloadable formats

• Weller Media Products
  http://dlcwest.com/~wmp/Books.html
  Directory of electronic books

Back to index

Obtaining Digital Images

Digital images come in several formats as well. Images available from the Web are likely to come in the CompuServe GIF format (filenames ending with *.gif) or JPEG format (*.jpg). These formats sacrifice image quality by compressing data to obtain a small file size, and are usually at the relatively coarse resolution of a computer monitor. These formats are often adequate for most needs, particularly for on-screen use, as opposed to printing. Higher quality images are available in Kodak PhotoCD format or TIFF format (*.tif or *.tiff).

These image formats are all called raster images, meaning they are composed of dots, and are used mainly for photographs and icons. Another type--a vector image--is composed of mathematical descriptions of the lines without any specific dots. Vector images can be scaled to any size without a loss of resolution. Vector images are comparable to ASCII text in that the essential information is stored rather than the actual dots. However, vector images are less practical for general-purpose use; they require specialized software and may display slowly. The most common file type is Encapsulated PostScript (*.eps).

Sometimes you may want to use an image that you find embedded in a Web page. Newer browsers make this process simple. On Windows machines, hold the mouse over the image and click the secondary mouse button (the right button) to bring up a shortcut menu with an option to "save image as...." Save the image as you would any file. On Macintosh machines, hold the Control button while clicking on the image with the mouse (or click and hold the mouse button) to bring up the shortcut menu.

Following are some sources of digital images:

• Yahoo! Search Page for Stock Photography
  http://www.yahoo.com/Business_and_Economy/
  Companies/Photography/Stock_Photography/
  A large number of commercial stock-photography resources are available from this site.

Back to index

Obtaining Digital Sound

Digital sound comes in three major formats that correspond to the three computer platforms. Unix machines use the old Audio format (filenames ending with *.au). Windows machines use the Wav format (*.wav) and Macintoshes use the QuickTime format (*.mov). A newer format is the Audio Interchange File Format (*.aiff). The formats are now mostly interchangeable, but our experience is that *.au works the best across platforms. Sound files often save space by using a low sampling rate (the number of times per second the sound wave is measured). For instance, by default Wav files sample at 11 MHz, while CD-quality sound is 44 MHz, four times as high. This tradeoff between sound quality and file size is similar to that between resolution and file size for images (see Images, above).

RealAudio (*.ra) has gained attention on the Internet recently. While the file format is much like the above types, it is designed to work differently. Most audio files must be downloaded in their entirety before they can be played. RealAudio files, like RealVideo files, the file begins to play before the entire file has been transmitted. In fact, only the part that is actually playing is stored on a local computer. This is great for Internet uses, but since it is difficult to download RealAudio files, it is not very practical for off-line use.

In contrast to the above formats, MIDI (*.mid or *.midi) is not a recording format, but a language used in electronic synthesizers. Instead of storing the shape of the sound wave, MIDI stores information about playing the synthesizer, such as which key to strike, how hard, which voice to use, etc. The synthesizer uses that information to generate a sound wave. As such, MIDI is significantly more compact than digital sound formats. Playback options, however, are limited by the capabilities of an individual computer. MIDI is to recorded digital sound as a vector graphic is to a raster graphic, and ASCII text is to graphical text.

Following are some sources of digital sound:

• MovieWavs
  http://www.moviewavs.com/
  Sound clips from the movies and TV, available in several formats.

• Xavier Media MIDI Archive
  http://misc.webworld.nu/midi/
  Sound files of music from films, television, and pop music in MIDI format

• Movies At Home Midi Page
  http://ecreations.com/movies/sound/index.shtml
  Sound files from the movies in MIDI format

Back to index

Obtaining Digital Movies

Digital movie formats are still evolving. Since they consist of a series of pictures presented in rapid succession, they can take up disk space and RAM (random access memory) very quickly. Most formats include compression devices which reduce the size and quality of the video image. A movie can consist of several tracks--for example, a video track and an audio track--that play together. Many formats allow the addition of other tracks, such as a text/captioning track or a secondary language sound track, increasing their usability along with their size.

The two oldest and most common movie formats are Apple QuickTime (filenames ending with *.mov) and MPEG (*.mpg or *.mpeg). MPEG is a compressed format suitable for use on the Internet. QuickTime is widely available--especially on the Macintosh platform--and the file format is evolving to take advantage of new technologies. Another format that has gained visibility and incorporates high potential for interactivity, is Shockwave. Like QuickTime, it requires a special program to play.

RealVideo (*.ra) has gained attention on the Internet recently. While the file format is much like the above types, it is designed to work differently. Other movie formats on the web require that the file be downloaded completely before it can be viewed. With RealVideo, the file begins to play before the entire file has been transmitted. In fact, only the part that is actually playing is stored on a local computer--a convenient feature for Internet users. Unfortunately, RealVideo files are difficult to download making them somewhat impractical for off-line use.

Following are some sources of digital video:

• CNN - Video Vault
  http://www.cnn.com/video_vault/
  Video clips from the CNN archives

Back to index