If you need a quick definition or visual example of a mathematics term, A Maths Dictionary for Kids is an awesome site. Produced by Australian teacher Jenny Eather, this FREE online dictionary contains over 600 math words, complete with examples and activities. Teachers really do know best…
http://www.amathsdictionaryforkids.com/
If you know of a science site of similar quality, let me know and I will post it here. Enjoy!