A 2D Physics simulation software ideal for educational purposes
Using its tools you can create various physical objects on a scene. You can for example create circles, rectangles, polygons, gears, chains, ropes, balloons and lots of other physics items. You can also connect those items using springs, pulleys, nails etc. This way you can create various scenes/scenarios which range from simple educational experiments to complex structures and mechanisms.
The program is available both for Linux (32 and 64-bit) and Windows.