With this program, one can draw images to see the effect of gravitational lensing. You can easily test the effects of several parameters by changing them and redrawing the image.

Time Flies, a great way to teach children how to read analog clocks in an ever increasing digital world. 4 different activities to choose from with various degrees of difficulty, three different types of printable works sheets, and much much more...

Try to play jinglebells. This game show you a note sheet. You need to press notes on virtual piano. Try to play jingle bells.