Have you seen that amazing 2D physical simulator called Phun? If not, this is a really fantastic program that you can download for FREE. Phun allows you to quickly and easily model real-world systems in a graphical manner to illustrate the effects of friction and gravity and all sorts of stuff.
It's GREAT for kids of all ages (including me). If we'd had something like this at school when I was a kid I'd be a genius now! (Of course we didn’t even have computers when I was at school, but that's a tale for another day.)
Honestly, this program is amazingly cool. This is the sort of thing I wish I had created myself. I ran across it a couple of months ago and have been having fun with it ever since. Using Phun, you can quickly and easily create 2D versions of scenes comprising multiple elements like blocks and gears and hinges and springs and levers and water and ... all sorts of things.
Once you've placed all of your elements in their initial positions, you click the Play button to see what will occur. If you have placed a stone in the air, for example, then it will be pulled down by gravity. If this stone subsequently hits another object, the result will depend on things like their relative sizes, masses, speeds, and material properties like frictional coefficients and so forth.
As illustrated in the YouTube video above, one very important aspect to this program is its ease-of-use. I'm tempted to compare it to the BASIC programming languages and usage model. With BASIC you can edit an existing line of code or add some new code and then immediately run it to see what happens. Similarly, in Phun you can rewind a simulation, resize or move existing elements around (just drag them with your mouse), add new elements, and click the Play button to see what happens now...
You can download a free copy of Phun by Clicking Here
(and here's a link to a Tutorial
). And, of course there are a whole bunch of Phun Videos on YouTube
– for example here's one I found of an adding machine using marbles:
Over time, Phun evolved into a more-sophisticated program called Algodoo – you can see the new site and download a demo by Clicking Here
. Algodoo is significantly more powerful than Phun and has more capabilities and better documentation, but there is a modest charge associated with it ... so "you pays your money and you makes your choice" as they say.
For myself, I'm more than happy with my free copy of Phun.