Whether or not one believes Khan Academy is helping to reinvent education, it’s hard to dispute the fact that Khan (and now his team) are an educational video-producing machine, or that the platform continues to diversify. In part, that started with the release of its iPad app in March. This week, Khan Academy brought its 3,500 videos to the iPhone.

K12 在线教育的领跑者 可汗学院在今年 3 月份发布了自己的 iPad 教学视频，本周，可汗学院继续发力移动端，推出了自己的 iPhone 教学应用，超 3500 个教学视频现在触手可及。

Nonetheless, the online learning academy continues to press on. As part of the latest update to its iPad app, the company added support for the iPhone, which now allows users to access its library of videos on the go. Unlike Khan’s iPad and web apps, the new app doesn’t include the ability to download the videos so that they can be watched offline, subtitles, or track your progress through the academy and unlock achievements. Instead, the app simply allows you to watch videos.

可汗学院在今年 3 月份发布的 iPad 增强版支持设备之间的时间同步，而且还加入了交互式的讲座文本以便于用户搜索。不过，跟可汗的 web 应用和 iPad 应用不同，这款 iPhone 应用目前的功能还比较初级，只允许学生在线观看视频，没有相应的字幕，不支持离线观看，另外也无法跟踪学生的学习进度。

This might make the app seem undercooked — and in a way it is — but it could actually be a smart move given the limited form factor. Stuffing the entire Khan Academy experience onto the iPhone’s screen likely would diminish the experience of its visualization tools, interactive transcriptions and some of its better gamification and progress-tracking features.

你可能很好奇，为何它的 iPhone 版应用会如此简陋。考虑到 iPhone 的体型和参数限制，将整个教学体验、包括各类视觉工具、交互式的视频文本、游戏机制和进度跟踪一下子一股脑儿封装到里面似乎不太可能。与其如此，可汗学院先将那部分最核心的内容，即视频本身尽快呈现给读者，似乎并没有错。

Nonetheless, by opening up the Khan experience to iPhone users, they can now access Khan’s instructional videos on the go, while on the bus or during long car rides — all of which is huge for students and fans of the educational platform.

另外，在线教育的一个很大优势在于打破地理、时间的限制，让学生随时随地可以学习，所以可汗学院的 Android 版应用也有望在不久的将来推出。

Sal Khan started out creating tutorials on Yahoo’s Doodle Pad to help his cousin do her math homework. When other family members began asking for help, he posted them on YouTube. Fast forward to the present and Khan has gone on to create some 3,600 videos, which collectively have been viewed over 210 million times. Along the way, his instructional library became Khan Academy and gained support from the Doerrs, Bill Gates and many others, and Khan himself became the “teacher of the world” and the “Messiah of Math.”

最后，可汗学院的教学视频累计观看次数已经达到 2 亿 1 千万次，而 Slam Khan 本人也被称为“teacher of the world”，世界之师，足见其影响力。