The ubiquity of information technology (IT) in our daily lives is obvious and everybody acknowledges its usefulness in education. This article focuses on the use of IT to facilitate learning, highlights different aspects of using IT in teaching and learning and explains why the potential of IT in teaching and learning may be underestimated.

We learn daily from experience; our minds and behaviours are shaped by our interaction with people and the environment. Our mind interprets a continuous stream of multimodal sensory data received from our five senses (touch, smell, vision, hearing and taste), and transforms these into knowledge, personality traits and other attributes that define a person. To increase or to make learning more efficient, we go to school, read books, watch movies, engage in intellectual discourse and activities (e.g. play, work) with one another. The auditory and visual senses are perhaps most widely-used when one is learning in an educational institution. Learning is also supplemented by other senses (e.g. our sense of smell in laboratory experiments in chemistry).

But what is the role of IT in learning? How can IT facilitate learning? There are many answers to these questions, but I believe one of the ways IT facilitates learning is its ability to simulate a system according to some mathematical model. A system here can refer to a phenomenon, an event, a tool, a machine, or anything we can imagine. It can also represent reality or something fictitious. A system accepts inputs, produces outputs and has internal parameters which describe its current state. A mathematical model consisting of equations describes the timed evolution of both outputs and internal parameters of the system in response to various inputs.

I believe the most important role of IT in learning is its ability to create virtual worlds that we can experience in any way that we, as its creators or inhabitants, prefer. In other words, IT empowers its human creators to create artificial worlds with rules of nature defined by their creators. The following are different levels of control that facilitate the learning experience and perhaps, develop the inner creative abilities:

• Time: Users dictate how fast or slow time progresses in the virtual worlds. By controlling the pace, users can experience their worlds in slow motion or at high speeds.
  
  
• Scales and levels of detail: Another useful feature is the ability to experience different levels of details. For example, one can zoom in and stay inside a machine's part or component that one is designing and witness how the machine works.
  
  
• Amplification or attenuation of senses: Users or inhabitants interact with the created world using human senses (e.g. sight, touch, hearing). As users interact with the world, the rules defining the world produce the required sensory data that can be amplified or reduced to achieve different levels of sensitivities. The user experiences these data through 'interface devices' that connect users with the virtual world.

The most common interface devices are the keyboard, mouse, joysticks, display and sound. The keyboard, mouse and joysticks allow users to input motion and the virtual world responds through a display (images) and sound. Currently, there are more advanced interface devices that provide 3-D motion input capabilities and more sensory interfaces (e.g. touch). We are starting to see such devices in the computer gaming world where the player wears certain devices and interacts directly with a computer display. One interesting class of input/output devices is joysticks with vibration capabilities such as those in Microsoft's Xbox and Sony's gaming consoles. Different levels of vibration simulate different magnitudes of explosions or impact.

Another class of systems is those that capture the user's motions such as PlayMotion (http://www. playmotion.com). With this system, the user can use his/her hands to push balls that are floating in the air. The system captures the real motion of the user's hand and shows a virtual hand on the display. The user literally sees his/her virtual hand on the display moving together with his physical hands while manipulating virtual objects on the screen (virtual world).

In the prototype and early commercialisation stages is a class of interfaces devices called haptic devices. A haptic device is essentially a small little robot (with many links connected by motors) that acts as a joystick. A handle is attached to the tip of the robot, which the user holds and moves to command 3-D motion in the virtual world. The motors at the joints of the robot exert varying levels of resisting torques so that the user, while holding on to the handle, can experience different levels of resistance. A haptic device that mimics a scalpel used in surgery can be used by trainee surgeons to practise surgery on an internal organ. As the doctor moves the virtual scalpel using the handle of the haptic device, he/ she is able to feel the forces as tissues are cut and visualise the whole operation at the same time. The virtual experience can be made more realistic if sound and images are added to simulate blood flow at different amplification levels (see
http:/guppy.mpe.nus.edu.sg/~haptics.htm for some examples of haptic devices).

In summary, we interact with the real world and learn from our successes and failures. Information technology allows the creation of interactive digital media coupled with rich user interfaces that facilitate experiential learning. The virtual worlds created by interactive digital media allow users to experience environments, which follow either the same or different sets of rules as the real world, at different levels. This certainly enhances user's learning experience, facilitates learning and promotes creativity.