Google Earth: Who doesn't love Google Earth? Whether you use it on a SmartBoard, desktop, or on your iPod touch, you can't fail to be impressed by what you can get for free from Google. Spin the globe or navigate the planet with a swift swipe of your finger, zoom in and out by pinching, and tilt the world by tilting your iPod touch. Students love it. The iPod touch and iPhone version includes all the same hi-res images you get on the desktop version, can easily be used by both Science and Social Studies teachers, but it does need 211 mb of free space and a WiFi connection.
Planets: The publishers of this popular star gazing app claim over 2.5 million downloads so far. You can view the solar system and constellations in 2D or 3D renderings, and find facts and information on all the planets and their moons. It shows sun rise and sunset times, as well as moon phases. For what it provides, this app has few, if any, rivals and it does it all for free. This is one of the best Apple iPod touch apps available for educators.
The Chemical Touch (Lite): Save yourself the hassle of carrying around a textbook, when all you need is your iPod touch. The Chemical Touch Lite provides a clear and simple periodic table. Mass, density, boiling points, and more are available for each of the color coded elements, and if that is not enough, the Internet button will connect you to the Wikipedia entry for the element in question. It is also available in French and other languages too.
NASA: The NASA app is a must for any space related projects. There are an extensive collection of images and videos that catalog the most important moments in space flight history. Launch information, countdown clocks, mission histories, and pictures of the day are just some of the great features you can look forward to. You can even track the movements of the International Space Station as it orbits the Earth, and find out what time you may be able to best see it from the ground.
Constitution for iPhone or iPod Touch: Students of American history cannot fail to be impressed by this digital version of an historic document. It lets you read through all the articles and amendments in a clear and easy to read format. There are also notes from the publisher on individual entries. Why not pair this app with other important documents like the Declaration for Independence or the Geneva Convention. They are made by the same publishers, and are also free to download.