When you first fire up the application, you'll immediately notice how simple and straight-forward the interface is. This is the type of application that a preschooler could most likely use on their own and not have difficulty with. (If you're not familiar with the guided access feature for iOS devices, it locks users out of any applications you don't want them to use and can be excellent for schools and children. Here's a great guide.)
Once you're inside the application, all you have to do is tap on a letter to begin learning. Each letter includes narration, more information about the word, and some type of interactivity. You can also change the narration from American English to British English.
A lot of the letters are really enjoyable, and the interactivity is educational as well. For example, on "X is for X-Ray" students can look at the moon under different types of wavelengths, from x-ray to microwave to infrared.
The added information on the left side is also a nice addition. At first, I was a little disappointed with it, because the reading level is pretty advanced on a lot of them. But, after thinking about it, it's a great addition for parents who are using the app with their children. They can read the information and talk about the material with their child. The only thing I would suggest here is to add narration as well, that way the kids could have the info read to them.
And essentially, that's the app! It's incredibly simple to use, but it packs a ton of content. The letters are fun, the interactivity is great, and the added information is nice for children using the app with their parents.
In my mind, the Common Extract team has taken a very simple idea, and packed it full of lots of great content, information, and fun. Plus, it's an excellent way to get students excited about space. And, if you like the app, they also have "ABC for Little Scientists."