Online Physics Games are Fun to Play.

If you haven't tried playing physics games online  you don't know what you are missing.  With some websites dedicated exclusively to physics games there are hundreds of good games to choose from.  What makes a game a physics game you ask? Elements in the game respond to the physics we would expect in the natural world.  Gravity makes objects fall, round objects roll, friction causes drag on objects, things balance and swing and have inertia just like they would in real life.
One of the nicest things about physics games is that they imitate life and what you've learned in the real world.  So your intuitive thought that a certain bridge design "just looks wrong" and won't hold weight is probably correct.

Greg's Top 3 Picks for physics games;
If you want to get started, here are 3 very playable games you will enjoy trying.

Crush the Castle 2 (destruction, projectile) by Armor Games.  With 16 million plays and a solid 9/10 rating this arguably the best game to come from Armor. You are a siege master responsible for knocking down lots of castles using your trebuchet and all kinds of projectiles.

 Wallaces Workshop (construction, cause and effect, projectile).

World of Goo  (building) by 2D Boy gamesAdmittedly not an online game running in flash, but such a playable game its worth checking out. (a generous demo version is available)

Types of physics games.

• Demolition games, normally using explosions projectiles or removal of structural elements to reach a goal.
• Construction games, where a structure you build needs to meet certain goals such as bearing a load.
• Cause and Effect games, where objects in the environment will interact so timing and results are important to achieve the goal.
• Stacking games where objects are piled (carefully) to meet some criteria.
• Projectile games, objects flying through the air with velocity, air resistance and trajectory to reach a goal.
• Immersive 3d environment games featuring all these aspects of physics games as well as particle physics, rag-doll physics, realistic light physics and more. (Games like HalfLife2 are not usually played online).

Some sites with Physics Games.
Here are some sites I've found that contain physics games; (please go ahead add your favourite physics game site and a description in the comments)
http://www.physicsgames.net
http://www.armorgames.com
http://www.kongregate.com/

Do you have a favourite physics based game or know of a site featuring these games? Let me know in the comments and I'll check it out.

Cheers,
Greg.