Last week we wrote about Digital Life - the rise of life-like digital experiences. We argued that online worlds like Second Life are becoming increasingly more engaging because of their realism. We noted that Second Life succeeds because it brings to the digital world real economics, geography and, of course, physics. Last week we also wrote about iPhone and why it might really matter. This week we are going to look at iPhone from the perspective of Digital Life.

Many agree that the iPhone is a breakthrough handheld device. It has many impressive qualities, but perhaps one of the most interesting ones is that it leverages and even bends the laws of physics. Apple's software is tuned to respond to our hand gestures in a way that makes an impression of interaction with the physical object. Yet, the interactions are fundamentally digital. Everything feels light and easy because there is no friction.

It is likely that Apple's iPhone will be just the beginning of many devices that will leverage what we will call here Digital Physics - an experience that is rooted in a real world phenomenon, but also takes advantage of the limitless power of software.

What is Digital Physics?

For people who play video games, Digital Physics is old news. For the rest of us, the Digital Physics experience is new. The traditional Windows desktop of the nineties never delivered life-like experiences. Instead, users where forced to learn to interact with computers by learning new gestures, via mice and keyboard. The modern interface from Apple changed that paradigm somewhat, by introducing digital interfaces that responded to mouse clicks. iPhone takes this experience to a whole new level, letting us interact with digital information using our hands.

The experience that Apple created in iPhone is Digital Physics. The primary characteristic of it is realism, because the interactions feel real. However the experience is not exactly like a physical world experience. Instead, it is a lighter, frictionless sort of interaction. Because it is frictionless, it is also faster. With a single motion it is possible to move a "mountain" of digital data.

The key point about Digital Physics is that it's intuitive; it does not to make the user work hard. The goal is to have an interface that is obvious. For decades we struggled with software that surprised us, because it behaved nothing like we would expect it to. The software that follows the laws of Digital Physics does not have this problem. It is simple to use, because it leverages the metaphors that we use every day in our real life.

How does Digital Physics work?

When you encounter Digital Physics in software, it seems magical at first. In fact, the magic is done by mimicking real life. The life-like behavior of software in devices like the iPhone is created by plugging in formulas from real physics. For example, you can apply gravity and viscosity formulas to create a very realistic motion.

Back in the late nineties I worked at a visualization company called Thinkmap, which was one of the first companies to apply Digital Physics methods to information visualization. Their flagship product is called Visual Thesaurus, which even today remains one of the best examples of life-like interactive experiences online. The motion in all Thinkmap software works by creatively combining physical forces. The animation is produced by continuously recalculating the current impact that forces have on each Thinkmap node.

Digital Physics in iPhone

It is very likely that engineers at Apple are also being inspired by how things work in nature. In this first version of iPhone, we already see a set of interesting examples of Digital Physics:


This is likely to become the most identified gesture in the iPhone. By putting their finger down on the device and performing a light downward rub, a user can scroll through contacts lists, emails and album covers. The motion has a distinct realistic quality, as the objects first accelerate and then decelerate. The motion is rapid, yet not hard on the eyes and obviously was nurtured to perfection by Apple's engineers.


The slide is the same gesture as the scroll, but the effect on the digital object is different. Sliding lets iPhone users control the volume of the unit, or frame in a YouTube clip and other movies. The slider response with just the right amount of resistance, making it a pleasure to use.


Zooming on the iPhone is done via two different gestures - pinching and double-tapping. While the double-tap is certainly simple and easy to master, even for people who can't double click, pinching is what steals the show. The user can place two fingers on the device at the same time and perform a reverse pinch to zoom in. This is really slick and, more importantly, intuitive.

There are many other elements of the iPhone user interface that creatively combine the physical and digital. For example, all buttons on the home screen look like real buttons. This effect is achieved by having a black background and reflective surface look. The editors automatically pop-up a magnifying glass when you are trying to insert text. By default, the keyboards makes sounds that resemble physical keyboards (although I turned this off quickly!). There are so many little things, design solutions and nuances that focus on the parallels between the digital and physical, that you will be discovering them for months.


The iPhone is not only a breakthrough handheld device, it is a device that brings a mesh of digital and physical to the masses. Apple achieved it by turning a phone (and ipod, video player and more) into software that creates a life-like experience, but also adds a digital lightness and playfulness. It is likely that we are going to see more devices that let us interact with information in this way. How does it suit you? If you have played with an iPhone, please let us know what you think. What other Digital Physics experiences in the iPhone did you find compelling?

Zooming pic: magerleagues

Disclaimer: Alex Iskold is a shareholder of the Thinkmap, Inc.