There are plenty of educational games which help to be both informative and engaging, without feeling like a chore! Many free choices are avaliable through abandonware games, which may need a little input to get working on newer machines.
An old space simulator that lets you pilot various spacecrafts, ranging from NASA space shuttles to futuristic space stations. Excellent details (especially planets in SVGA resolution), realistic space flight dynamics, and versatile camera & film options. The steep learning curve is eased by excellent on-line tutorials and help files. Note: The game has long been discontinued by Microsoft, but its legacy lives on. Check out Orbiter, an outstanding (and free!) space flight simulation that is continually being developed and expanded.
This a game teaches players about the solar system. The player flies in a rocket ship throughout the solar system, questioning various alien lifeforms in order to solve the theft of an important part of the solar system (e.g. Saturn's rings). There is only a limited amount of fuel available for travel, so if the player doesn't ask the right questions on the right planets, or follows the wrong clues, the criminal(s) will get away, leaving the player to start over again with another crime.
This is an adventure and educational game. The player joins Nye labs and performs various science experiments.
A variety of science themed games that can be played with a web browser.
Draw an iceberg and see how it will float. Only web browser needed.