Yes. You don't need specific permission from me but if you do something interesting it would be nice if you let me know.

Unless stated otherwise all content is covered by a Creative Commons licence. (The Creative Commons Attribution - NonCommercial - ShareAlike 1.0 (UK) licence).

The intention is to allow the use of the material for non-commercial purposes without too much fuss. In short you are allowed to do what you want with the material, including making and distributing derivative works so long as you satisfy these three conditions:

• Attribution. Give credit to the original source. Just leaving the original copyright notices alone or providing a link to www.subtangent.com will suffice.
• Non-commercial. You can't charge for these resources (other than a reasonable fee for copying) or put them on a website that requires a paid subscription or requires people to view advertising before they can be accessed.
• Share Alike. Any derivative works you distribute must be made available under the same licence.

You also have the option of the GNU GPL for any of the software here, if you would prefer that. This is your best choice if you want to use the software commercially. If you want to use the software commercially in a non-GPL project then email me and we can negotiate a price.

Teachers use, modify, share and copy resources all the time but very often they are operating within a legal grey area when they do this. One of the key responsibilities of teachers is to select resources and modify them to suit their students. Many teachers in the UK are under the illusion that there is a general educational exemption from copyright law that lets them do this. This is not the case. The internet provides a powerful medium for allowing teachers to build collaborative networks, but if you download copyrighted material from the internet you generally have no legal right to actually use that material in a classroom unless the copyright owner specifically gives permission.

Online educational resources are of benefit to my students, and to society in general. I want the resources I develop to be available to others. That's sharing, and I think sharing is good, so I explicity use a licence that encourages sharing.

Most of the flash movies on this site can be used offline. Here are a couple of good ways of saving them locally:

Method 1

Look for the 'Bigger' link under the movie. Right-clicking here will often bring up a context menu that lets you save the file it links to:

Mozilla Firefox

Internet Explorer

Method 2

You can save the entire page for offline use:

Mozilla Firefox

Internet Explorer

Make sure you select the 'Web page, complete' option.

Using offline

You should be able to just load the saved movies/pages into your web browser but some movies -- those marked with an asterisk -- may need some more work. See the source code page for more help here.

You might find a Flash stand alone player to be useful too.

I'd like to hear it! You can use the feedback form to send me a message.

Yes! You can use the feedback form to send me a message.

Probably nothing unless it's really awful. I make no representations that this site is suitable for any particular age and I have no control over sites that I link to.

If you have children under your care for whom you wish to allow unsupervised web access but nonetheless wish to restrict the sites they visit then you should ask your network administrator to restrict access to web pages based on their PICS rating.

I'm Duncan Keith, a mathematics teacher in England.